Stop sub-classing object (#8249)

168 files changed, 293 insertions, 292 deletions

diff --git a/changelog.d/8249.misc b/changelog.d/8249.misc
new file mode 100644
index 0000000000..6a42e8a4e6
--- /dev/null
+++ b/changelog.d/8249.misc
@@ -0,0 +1 @@
+Stop sub-classing from object.
diff --git a/contrib/cmdclient/http.py b/contrib/cmdclient/http.py
index e2534ee584..cd3260b27d 100644
--- a/contrib/cmdclient/http.py
+++ b/contrib/cmdclient/http.py
@@ -24,7 +24,7 @@ from twisted.web.client import Agent, readBody
 from twisted.web.http_headers import Headers
 
 
-class HttpClient(object):
+class HttpClient:
     """ Interface for talking json over http
     """
 
@@ -169,7 +169,7 @@ class TwistedHttpClient(HttpClient):
         return d
 
 
-class _RawProducer(object):
+class _RawProducer:
     def __init__(self, data):
         self.data = data
         self.body = data
@@ -186,7 +186,7 @@ class _RawProducer(object):
         pass
 
 
-class _JsonProducer(object):
+class _JsonProducer:
     """ Used by the twisted http client to create the HTTP body from json
     """
 
diff --git a/contrib/experiments/cursesio.py b/contrib/experiments/cursesio.py
index ffefe3bb39..15a22c3a0e 100644
--- a/contrib/experiments/cursesio.py
+++ b/contrib/experiments/cursesio.py
@@ -141,7 +141,7 @@ class CursesStdIO:
         curses.endwin()
 
 
-class Callback(object):
+class Callback:
     def __init__(self, stdio):
         self.stdio = stdio
 
diff --git a/contrib/experiments/test_messaging.py b/contrib/experiments/test_messaging.py
index a84ec4ecae..d4c35ff2fc 100644
--- a/contrib/experiments/test_messaging.py
+++ b/contrib/experiments/test_messaging.py
@@ -55,7 +55,7 @@ def excpetion_errback(failure):
     logging.exception(failure)
 
 
-class InputOutput(object):
+class InputOutput:
     """ This is responsible for basic I/O so that a user can interact with
     the example app.
     """
@@ -132,7 +132,7 @@ class IOLoggerHandler(logging.Handler):
         self.io.print_log(msg)
 
 
-class Room(object):
+class Room:
     """ Used to store (in memory) the current membership state of a room, and
     which home servers we should send PDUs associated with the room to.
     """
diff --git a/scripts-dev/hash_history.py b/scripts-dev/hash_history.py
index bf3862a386..89acb52e6a 100644
--- a/scripts-dev/hash_history.py
+++ b/scripts-dev/hash_history.py
@@ -15,7 +15,7 @@ from synapse.storage.pdu import PduStore
 from synapse.storage.signatures import SignatureStore
 
 
-class Store(object):
+class Store:
     _get_pdu_tuples = PduStore.__dict__["_get_pdu_tuples"]
     _get_pdu_content_hashes_txn = SignatureStore.__dict__["_get_pdu_content_hashes_txn"]
     _get_prev_pdu_hashes_txn = SignatureStore.__dict__["_get_prev_pdu_hashes_txn"]
diff --git a/synapse/api/auth.py b/synapse/api/auth.py
index 7aab764360..75388643ee 100644
--- a/synapse/api/auth.py
+++ b/synapse/api/auth.py
@@ -58,7 +58,7 @@ class _InvalidMacaroonException(Exception):
     pass
 
 
-class Auth(object):
+class Auth:
     """
     FIXME: This class contains a mix of functions for authenticating users
     of our client-server API and authenticating events added to room graphs.
diff --git a/synapse/api/auth_blocking.py b/synapse/api/auth_blocking.py
index 49093bf181..d8fafd7cb8 100644
--- a/synapse/api/auth_blocking.py
+++ b/synapse/api/auth_blocking.py
@@ -22,7 +22,7 @@ from synapse.config.server import is_threepid_reserved
 logger = logging.getLogger(__name__)
 
 
-class AuthBlocking(object):
+class AuthBlocking:
     def __init__(self, hs):
         self.store = hs.get_datastore()
 
diff --git a/synapse/api/constants.py b/synapse/api/constants.py
index 6a6d32c302..46013cde15 100644
--- a/synapse/api/constants.py
+++ b/synapse/api/constants.py
@@ -28,7 +28,7 @@ MAX_ALIAS_LENGTH = 255
 MAX_USERID_LENGTH = 255
 
 
-class Membership(object):
+class Membership:
 
     """Represents the membership states of a user in a room."""
 
@@ -40,7 +40,7 @@ class Membership(object):
     LIST = (INVITE, JOIN, KNOCK, LEAVE, BAN)
 
 
-class PresenceState(object):
+class PresenceState:
     """Represents the presence state of a user."""
 
     OFFLINE = "offline"
@@ -48,14 +48,14 @@ class PresenceState(object):
     ONLINE = "online"
 
 
-class JoinRules(object):
+class JoinRules:
     PUBLIC = "public"
     KNOCK = "knock"
     INVITE = "invite"
     PRIVATE = "private"
 
 
-class LoginType(object):
+class LoginType:
     PASSWORD = "m.login.password"
     EMAIL_IDENTITY = "m.login.email.identity"
     MSISDN = "m.login.msisdn"
@@ -65,7 +65,7 @@ class LoginType(object):
     DUMMY = "m.login.dummy"
 
 
-class EventTypes(object):
+class EventTypes:
     Member = "m.room.member"
     Create = "m.room.create"
     Tombstone = "m.room.tombstone"
@@ -96,17 +96,17 @@ class EventTypes(object):
     Presence = "m.presence"
 
 
-class RejectedReason(object):
+class RejectedReason:
     AUTH_ERROR = "auth_error"
 
 
-class RoomCreationPreset(object):
+class RoomCreationPreset:
     PRIVATE_CHAT = "private_chat"
     PUBLIC_CHAT = "public_chat"
     TRUSTED_PRIVATE_CHAT = "trusted_private_chat"
 
 
-class ThirdPartyEntityKind(object):
+class ThirdPartyEntityKind:
     USER = "user"
     LOCATION = "location"
 
@@ -115,7 +115,7 @@ ServerNoticeMsgType = "m.server_notice"
 ServerNoticeLimitReached = "m.server_notice.usage_limit_reached"
 
 
-class UserTypes(object):
+class UserTypes:
     """Allows for user type specific behaviour. With the benefit of hindsight
     'admin' and 'guest' users should also be UserTypes. Normal users are type None
     """
@@ -125,7 +125,7 @@ class UserTypes(object):
     ALL_USER_TYPES = (SUPPORT, BOT)
 
 
-class RelationTypes(object):
+class RelationTypes:
     """The types of relations known to this server.
     """
 
@@ -134,14 +134,14 @@ class RelationTypes(object):
     REFERENCE = "m.reference"
 
 
-class LimitBlockingTypes(object):
+class LimitBlockingTypes:
     """Reasons that a server may be blocked"""
 
     MONTHLY_ACTIVE_USER = "monthly_active_user"
     HS_DISABLED = "hs_disabled"
 
 
-class EventContentFields(object):
+class EventContentFields:
     """Fields found in events' content, regardless of type."""
 
     # Labels for the event, cf https://github.com/matrix-org/matrix-doc/pull/2326
@@ -152,6 +152,6 @@ class EventContentFields(object):
     SELF_DESTRUCT_AFTER = "org.matrix.self_destruct_after"
 
 
-class RoomEncryptionAlgorithms(object):
+class RoomEncryptionAlgorithms:
     MEGOLM_V1_AES_SHA2 = "m.megolm.v1.aes-sha2"
     DEFAULT = MEGOLM_V1_AES_SHA2
diff --git a/synapse/api/errors.py b/synapse/api/errors.py
index 4888c0ec4d..94a9e58eae 100644
--- a/synapse/api/errors.py
+++ b/synapse/api/errors.py
@@ -31,7 +31,7 @@ if typing.TYPE_CHECKING:
 logger = logging.getLogger(__name__)
 
 
-class Codes(object):
+class Codes:
     UNRECOGNIZED = "M_UNRECOGNIZED"
     UNAUTHORIZED = "M_UNAUTHORIZED"
     FORBIDDEN = "M_FORBIDDEN"
diff --git a/synapse/api/filtering.py b/synapse/api/filtering.py
index a8937d2595..2a2c9e6f13 100644
--- a/synapse/api/filtering.py
+++ b/synapse/api/filtering.py
@@ -130,7 +130,7 @@ def matrix_user_id_validator(user_id_str):
     return UserID.from_string(user_id_str)
 
 
-class Filtering(object):
+class Filtering:
     def __init__(self, hs):
         super(Filtering, self).__init__()
         self.store = hs.get_datastore()
@@ -168,7 +168,7 @@ class Filtering(object):
             raise SynapseError(400, str(e))
 
 
-class FilterCollection(object):
+class FilterCollection:
     def __init__(self, filter_json):
         self._filter_json = filter_json
 
@@ -249,7 +249,7 @@ class FilterCollection(object):
         )
 
 
-class Filter(object):
+class Filter:
     def __init__(self, filter_json):
         self.filter_json = filter_json
 
diff --git a/synapse/api/ratelimiting.py b/synapse/api/ratelimiting.py
index e62ae50ac2..5d9d5a228f 100644
--- a/synapse/api/ratelimiting.py
+++ b/synapse/api/ratelimiting.py
@@ -21,7 +21,7 @@ from synapse.types import Requester
 from synapse.util import Clock
 
 
-class Ratelimiter(object):
+class Ratelimiter:
     """
     Ratelimit actions marked by arbitrary keys.
 
diff --git a/synapse/api/room_versions.py b/synapse/api/room_versions.py
index d7baf2bc39..f3ecbf36b6 100644
--- a/synapse/api/room_versions.py
+++ b/synapse/api/room_versions.py
@@ -18,7 +18,7 @@ from typing import Dict
 import attr
 
 
-class EventFormatVersions(object):
+class EventFormatVersions:
     """This is an internal enum for tracking the version of the event format,
     independently from the room version.
     """
@@ -35,20 +35,20 @@ KNOWN_EVENT_FORMAT_VERSIONS = {
 }
 
 
-class StateResolutionVersions(object):
+class StateResolutionVersions:
     """Enum to identify the state resolution algorithms"""
 
     V1 = 1  # room v1 state res
     V2 = 2  # MSC1442 state res: room v2 and later
 
 
-class RoomDisposition(object):
+class RoomDisposition:
     STABLE = "stable"
     UNSTABLE = "unstable"
 
 
 @attr.s(slots=True, frozen=True)
-class RoomVersion(object):
+class RoomVersion:
     """An object which describes the unique attributes of a room version."""
 
     identifier = attr.ib()  # str; the identifier for this version
@@ -69,7 +69,7 @@ class RoomVersion(object):
     limit_notifications_power_levels = attr.ib(type=bool)
 
 
-class RoomVersions(object):
+class RoomVersions:
     V1 = RoomVersion(
         "1",
         RoomDisposition.STABLE,
diff --git a/synapse/api/urls.py b/synapse/api/urls.py
index bd03ebca5a..bbfccf955e 100644
--- a/synapse/api/urls.py
+++ b/synapse/api/urls.py
@@ -33,7 +33,7 @@ MEDIA_PREFIX = "/_matrix/media/r0"
 LEGACY_MEDIA_PREFIX = "/_matrix/media/v1"
 
 
-class ConsentURIBuilder(object):
+class ConsentURIBuilder:
     def __init__(self, hs_config):
         """
         Args:
diff --git a/synapse/app/_base.py b/synapse/app/_base.py
index a43dc5b2c9..fb476ddaf5 100644
--- a/synapse/app/_base.py
+++ b/synapse/app/_base.py
@@ -349,7 +349,7 @@ def install_dns_limiter(reactor, max_dns_requests_in_flight=100):
     reactor.installNameResolver(new_resolver)
 
 
-class _LimitedHostnameResolver(object):
+class _LimitedHostnameResolver:
     """Wraps a IHostnameResolver, limiting the number of in-flight DNS lookups.
     """
 
@@ -409,7 +409,7 @@ class _LimitedHostnameResolver(object):
             yield deferred
 
 
-class _DeferredResolutionReceiver(object):
+class _DeferredResolutionReceiver:
     """Wraps a IResolutionReceiver and simply resolves the given deferred when
     resolution is complete
     """
diff --git a/synapse/app/generic_worker.py b/synapse/app/generic_worker.py
index 739b013d4c..f985810e88 100644
--- a/synapse/app/generic_worker.py
+++ b/synapse/app/generic_worker.py
@@ -745,7 +745,7 @@ class GenericWorkerReplicationHandler(ReplicationDataHandler):
             self.send_handler.wake_destination(server)
 
 
-class FederationSenderHandler(object):
+class FederationSenderHandler:
     """Processes the fedration replication stream
 
     This class is only instantiate on the worker responsible for sending outbound
diff --git a/synapse/appservice/__init__.py b/synapse/appservice/__init__.py
index 69a7182ef4..13ec1f71a6 100644
--- a/synapse/appservice/__init__.py
+++ b/synapse/appservice/__init__.py
@@ -27,12 +27,12 @@ if TYPE_CHECKING:
 logger = logging.getLogger(__name__)
 
 
-class ApplicationServiceState(object):
+class ApplicationServiceState:
     DOWN = "down"
     UP = "up"
 
 
-class AppServiceTransaction(object):
+class AppServiceTransaction:
     """Represents an application service transaction."""
 
     def __init__(self, service, id, events):
@@ -64,7 +64,7 @@ class AppServiceTransaction(object):
         await store.complete_appservice_txn(service=self.service, txn_id=self.id)
 
 
-class ApplicationService(object):
+class ApplicationService:
     """Defines an application service. This definition is mostly what is
     provided to the /register AS API.
 
diff --git a/synapse/appservice/scheduler.py b/synapse/appservice/scheduler.py
index d5204b1314..8eb8c6f51c 100644
--- a/synapse/appservice/scheduler.py
+++ b/synapse/appservice/scheduler.py
@@ -57,7 +57,7 @@ from synapse.metrics.background_process_metrics import run_as_background_process
 logger = logging.getLogger(__name__)
 
 
-class ApplicationServiceScheduler(object):
+class ApplicationServiceScheduler:
     """ Public facing API for this module. Does the required DI to tie the
     components together. This also serves as the "event_pool", which in this
     case is a simple array.
@@ -86,7 +86,7 @@ class ApplicationServiceScheduler(object):
         self.queuer.enqueue(service, event)
 
 
-class _ServiceQueuer(object):
+class _ServiceQueuer:
     """Queue of events waiting to be sent to appservices.
 
     Groups events into transactions per-appservice, and sends them on to the
@@ -133,7 +133,7 @@ class _ServiceQueuer(object):
             self.requests_in_flight.discard(service.id)
 
 
-class _TransactionController(object):
+class _TransactionController:
     """Transaction manager.
 
     Builds AppServiceTransactions and runs their lifecycle. Also starts a Recoverer
@@ -209,7 +209,7 @@ class _TransactionController(object):
         return state == ApplicationServiceState.UP or state is None
 
 
-class _Recoverer(object):
+class _Recoverer:
     """Manages retries and backoff for a DOWN appservice.
 
     We have one of these for each appservice which is currently considered DOWN.
diff --git a/synapse/config/_base.py b/synapse/config/_base.py
index 1417487427..ad5ab6ad62 100644
--- a/synapse/config/_base.py
+++ b/synapse/config/_base.py
@@ -88,7 +88,7 @@ def path_exists(file_path):
         return False
 
 
-class Config(object):
+class Config:
     """
     A configuration section, containing configuration keys and values.
 
@@ -283,7 +283,7 @@ def _create_mxc_to_http_filter(public_baseurl: str) -> Callable:
     return mxc_to_http_filter
 
 
-class RootConfig(object):
+class RootConfig:
     """
     Holder of an application's configuration.
 
diff --git a/synapse/config/cache.py b/synapse/config/cache.py
index aff5b21ab2..8e03f14005 100644
--- a/synapse/config/cache.py
+++ b/synapse/config/cache.py
@@ -33,7 +33,7 @@ _DEFAULT_FACTOR_SIZE = 0.5
 _DEFAULT_EVENT_CACHE_SIZE = "10K"
 
 
-class CacheProperties(object):
+class CacheProperties:
     def __init__(self):
         # The default factor size for all caches
         self.default_factor_size = float(
diff --git a/synapse/config/key.py b/synapse/config/key.py
index b529ea5da0..de964dff13 100644
--- a/synapse/config/key.py
+++ b/synapse/config/key.py
@@ -82,7 +82,7 @@ logger = logging.getLogger(__name__)
 
 
 @attr.s
-class TrustedKeyServer(object):
+class TrustedKeyServer:
     # string: name of the server.
     server_name = attr.ib()
 
diff --git a/synapse/config/metrics.py b/synapse/config/metrics.py
index 6aad0d37c0..dfd27e1523 100644
--- a/synapse/config/metrics.py
+++ b/synapse/config/metrics.py
@@ -22,7 +22,7 @@ from ._base import Config, ConfigError
 
 
 @attr.s
-class MetricsFlags(object):
+class MetricsFlags:
     known_servers = attr.ib(default=False, validator=attr.validators.instance_of(bool))
 
     @classmethod
diff --git a/synapse/config/ratelimiting.py b/synapse/config/ratelimiting.py
index b2c78ac40c..14b8836197 100644
--- a/synapse/config/ratelimiting.py
+++ b/synapse/config/ratelimiting.py
@@ -17,7 +17,7 @@ from typing import Dict
 from ._base import Config
 
 
-class RateLimitConfig(object):
+class RateLimitConfig:
     def __init__(
         self,
         config: Dict[str, float],
@@ -27,7 +27,7 @@ class RateLimitConfig(object):
         self.burst_count = config.get("burst_count", defaults["burst_count"])
 
 
-class FederationRateLimitConfig(object):
+class FederationRateLimitConfig:
     _items_and_default = {
         "window_size": 1000,
         "sleep_limit": 10,
diff --git a/synapse/config/room.py b/synapse/config/room.py
index 52cf0b62fc..692d7a1936 100644
--- a/synapse/config/room.py
+++ b/synapse/config/room.py
@@ -22,7 +22,7 @@ from ._base import Config, ConfigError
 logger = logging.Logger(__name__)
 
 
-class RoomDefaultEncryptionTypes(object):
+class RoomDefaultEncryptionTypes:
     """Possible values for the encryption_enabled_by_default_for_room_type config option"""
 
     ALL = "all"
diff --git a/synapse/config/room_directory.py b/synapse/config/room_directory.py
index 7ac7699676..6de1f9d103 100644
--- a/synapse/config/room_directory.py
+++ b/synapse/config/room_directory.py
@@ -149,7 +149,7 @@ class RoomDirectoryConfig(Config):
         return False
 
 
-class _RoomDirectoryRule(object):
+class _RoomDirectoryRule:
     """Helper class to test whether a room directory action is allowed, like
     creating an alias or publishing a room.
     """
diff --git a/synapse/config/server.py b/synapse/config/server.py
index 526a90b26a..e85c6a0840 100644
--- a/synapse/config/server.py
+++ b/synapse/config/server.py
@@ -424,7 +424,7 @@ class ServerConfig(Config):
         self.gc_thresholds = read_gc_thresholds(config.get("gc_thresholds", None))
 
         @attr.s
-        class LimitRemoteRoomsConfig(object):
+        class LimitRemoteRoomsConfig:
             enabled = attr.ib(
                 validator=attr.validators.instance_of(bool), default=False
             )
diff --git a/synapse/crypto/context_factory.py b/synapse/crypto/context_factory.py
index 777c0f00b1..2b03f5ac76 100644
--- a/synapse/crypto/context_factory.py
+++ b/synapse/crypto/context_factory.py
@@ -83,7 +83,7 @@ class ServerContextFactory(ContextFactory):
 
 
 @implementer(IPolicyForHTTPS)
-class FederationPolicyForHTTPS(object):
+class FederationPolicyForHTTPS:
     """Factory for Twisted SSLClientConnectionCreators that are used to make connections
     to remote servers for federation.
 
@@ -152,7 +152,7 @@ class FederationPolicyForHTTPS(object):
 
 
 @implementer(IPolicyForHTTPS)
-class RegularPolicyForHTTPS(object):
+class RegularPolicyForHTTPS:
     """Factory for Twisted SSLClientConnectionCreators that are used to make connections
     to remote servers, for other than federation.
 
@@ -189,7 +189,7 @@ def _context_info_cb(ssl_connection, where, ret):
 
 
 @implementer(IOpenSSLClientConnectionCreator)
-class SSLClientConnectionCreator(object):
+class SSLClientConnectionCreator:
     """Creates openssl connection objects for client connections.
 
     Replaces twisted.internet.ssl.ClientTLSOptions
@@ -214,7 +214,7 @@ class SSLClientConnectionCreator(object):
         return connection
 
 
-class ConnectionVerifier(object):
+class ConnectionVerifier:
     """Set the SNI, and do cert verification
 
     This is a thing which is attached to the TLSMemoryBIOProtocol, and is called by
diff --git a/synapse/crypto/keyring.py b/synapse/crypto/keyring.py
index 81c4b430b2..32c31b1cd1 100644
--- a/synapse/crypto/keyring.py
+++ b/synapse/crypto/keyring.py
@@ -57,7 +57,7 @@ logger = logging.getLogger(__name__)
 
 
 @attr.s(slots=True, cmp=False)
-class VerifyJsonRequest(object):
+class VerifyJsonRequest:
     """
     A request to verify a JSON object.
 
@@ -96,7 +96,7 @@ class KeyLookupError(ValueError):
     pass
 
 
-class Keyring(object):
+class Keyring:
     def __init__(self, hs, key_fetchers=None):
         self.clock = hs.get_clock()
 
@@ -420,7 +420,7 @@ class Keyring(object):
         remaining_requests.difference_update(completed)
 
 
-class KeyFetcher(object):
+class KeyFetcher:
     async def get_keys(self, keys_to_fetch):
         """
         Args:
@@ -456,7 +456,7 @@ class StoreKeyFetcher(KeyFetcher):
         return keys
 
 
-class BaseV2KeyFetcher(object):
+class BaseV2KeyFetcher:
     def __init__(self, hs):
         self.store = hs.get_datastore()
         self.config = hs.get_config()
diff --git a/synapse/events/__init__.py b/synapse/events/__init__.py
index 62ea44fa49..bf800a3852 100644
--- a/synapse/events/__init__.py
+++ b/synapse/events/__init__.py
@@ -96,7 +96,7 @@ class DefaultDictProperty(DictProperty):
         return instance._dict.get(self.key, self.default)
 
 
-class _EventInternalMetadata(object):
+class _EventInternalMetadata:
     __slots__ = ["_dict"]
 
     def __init__(self, internal_metadata_dict: JsonDict):
diff --git a/synapse/events/builder.py b/synapse/events/builder.py
index 7878cd7044..b6c47be646 100644
--- a/synapse/events/builder.py
+++ b/synapse/events/builder.py
@@ -36,7 +36,7 @@ from synapse.util.stringutils import random_string
 
 
 @attr.s(slots=True, cmp=False, frozen=True)
-class EventBuilder(object):
+class EventBuilder:
     """A format independent event builder used to build up the event content
     before signing the event.
 
@@ -164,7 +164,7 @@ class EventBuilder(object):
         )
 
 
-class EventBuilderFactory(object):
+class EventBuilderFactory:
     def __init__(self, hs):
         self.clock = hs.get_clock()
         self.hostname = hs.hostname
diff --git a/synapse/events/spamcheck.py b/synapse/events/spamcheck.py
index a7cddac974..b0fc859a47 100644
--- a/synapse/events/spamcheck.py
+++ b/synapse/events/spamcheck.py
@@ -25,7 +25,7 @@ if MYPY:
     import synapse.server
 
 
-class SpamChecker(object):
+class SpamChecker:
     def __init__(self, hs: "synapse.server.HomeServer"):
         self.spam_checkers = []  # type: List[Any]
 
diff --git a/synapse/events/third_party_rules.py b/synapse/events/third_party_rules.py
index 2956a64234..9d5310851c 100644
--- a/synapse/events/third_party_rules.py
+++ b/synapse/events/third_party_rules.py
@@ -18,7 +18,7 @@ from synapse.events.snapshot import EventContext
 from synapse.types import Requester
 
 
-class ThirdPartyEventRules(object):
+class ThirdPartyEventRules:
     """Allows server admins to provide a Python module implementing an extra
     set of rules to apply when processing events.
 
diff --git a/synapse/events/utils.py b/synapse/events/utils.py
index 2d42e268c6..32c73d3413 100644
--- a/synapse/events/utils.py
+++ b/synapse/events/utils.py
@@ -322,7 +322,7 @@ def serialize_event(
     return d
 
 
-class EventClientSerializer(object):
+class EventClientSerializer:
     """Serializes events that are to be sent to clients.
 
     This is used for bundling extra information with any events to be sent to
diff --git a/synapse/events/validator.py b/synapse/events/validator.py
index 5ce3874fba..9df35b54ba 100644
--- a/synapse/events/validator.py
+++ b/synapse/events/validator.py
@@ -20,7 +20,7 @@ from synapse.events.utils import validate_canonicaljson
 from synapse.types import EventID, RoomID, UserID
 
 
-class EventValidator(object):
+class EventValidator:
     def validate_new(self, event, config):
         """Validates the event has roughly the right format
 
diff --git a/synapse/federation/federation_base.py b/synapse/federation/federation_base.py
index 420df2385f..38aa47963f 100644
--- a/synapse/federation/federation_base.py
+++ b/synapse/federation/federation_base.py
@@ -39,7 +39,7 @@ from synapse.types import JsonDict, get_domain_from_id
 logger = logging.getLogger(__name__)
 
 
-class FederationBase(object):
+class FederationBase:
     def __init__(self, hs):
         self.hs = hs
 
diff --git a/synapse/federation/federation_server.py b/synapse/federation/federation_server.py
index 630f571cd4..218df884b0 100644
--- a/synapse/federation/federation_server.py
+++ b/synapse/federation/federation_server.py
@@ -785,7 +785,7 @@ def _acl_entry_matches(server_name: str, acl_entry: str) -> Match:
     return regex.match(server_name)
 
 
-class FederationHandlerRegistry(object):
+class FederationHandlerRegistry:
     """Allows classes to register themselves as handlers for a given EDU or
     query type for incoming federation traffic.
     """
diff --git a/synapse/federation/persistence.py b/synapse/federation/persistence.py
index de1fe7da38..079e2b2fe0 100644
--- a/synapse/federation/persistence.py
+++ b/synapse/federation/persistence.py
@@ -29,7 +29,7 @@ from synapse.types import JsonDict
 logger = logging.getLogger(__name__)
 
 
-class TransactionActions(object):
+class TransactionActions:
     """ Defines persistence actions that relate to handling Transactions.
     """
 
diff --git a/synapse/federation/send_queue.py b/synapse/federation/send_queue.py
index 4d65d4aeea..8e46957d15 100644
--- a/synapse/federation/send_queue.py
+++ b/synapse/federation/send_queue.py
@@ -46,7 +46,7 @@ from .units import Edu
 logger = logging.getLogger(__name__)
 
 
-class FederationRemoteSendQueue(object):
+class FederationRemoteSendQueue:
     """A drop in replacement for FederationSender"""
 
     def __init__(self, hs):
@@ -365,7 +365,7 @@ class FederationRemoteSendQueue(object):
         )
 
 
-class BaseFederationRow(object):
+class BaseFederationRow:
     """Base class for rows to be sent in the federation stream.
 
     Specifies how to identify, serialize and deserialize the different types.
diff --git a/synapse/federation/sender/__init__.py b/synapse/federation/sender/__init__.py
index 5276c1734f..552519e82c 100644
--- a/synapse/federation/sender/__init__.py
+++ b/synapse/federation/sender/__init__.py
@@ -56,7 +56,7 @@ sent_pdus_destination_dist_total = Counter(
 )
 
 
-class FederationSender(object):
+class FederationSender:
     def __init__(self, hs: "synapse.server.HomeServer"):
         self.hs = hs
         self.server_name = hs.hostname
diff --git a/synapse/federation/sender/per_destination_queue.py b/synapse/federation/sender/per_destination_queue.py
index f1534d431d..defc228c23 100644
--- a/synapse/federation/sender/per_destination_queue.py
+++ b/synapse/federation/sender/per_destination_queue.py
@@ -53,7 +53,7 @@ sent_edus_by_type = Counter(
 )
 
 
-class PerDestinationQueue(object):
+class PerDestinationQueue:
     """
     Manages the per-destination transmission queues.
 
diff --git a/synapse/federation/sender/transaction_manager.py b/synapse/federation/sender/transaction_manager.py
index 0ebc70d57d..c84072ab73 100644
--- a/synapse/federation/sender/transaction_manager.py
+++ b/synapse/federation/sender/transaction_manager.py
@@ -35,7 +35,7 @@ if TYPE_CHECKING:
 logger = logging.getLogger(__name__)
 
 
-class TransactionManager(object):
+class TransactionManager:
     """Helper class which handles building and sending transactions
 
     shared between PerDestinationQueue objects
diff --git a/synapse/federation/transport/client.py b/synapse/federation/transport/client.py
index 9ea821dbb2..17a10f622e 100644
--- a/synapse/federation/transport/client.py
+++ b/synapse/federation/transport/client.py
@@ -30,7 +30,7 @@ from synapse.logging.utils import log_function
 logger = logging.getLogger(__name__)
 
 
-class TransportLayerClient(object):
+class TransportLayerClient:
     """Sends federation HTTP requests to other servers"""
 
     def __init__(self, hs):
diff --git a/synapse/federation/transport/server.py b/synapse/federation/transport/server.py
index 5e111aa902..9325e0f857 100644
--- a/synapse/federation/transport/server.py
+++ b/synapse/federation/transport/server.py
@@ -100,7 +100,7 @@ class NoAuthenticationError(AuthenticationError):
     pass
 
 
-class Authenticator(object):
+class Authenticator:
     def __init__(self, hs: HomeServer):
         self._clock = hs.get_clock()
         self.keyring = hs.get_keyring()
@@ -228,7 +228,7 @@ def _parse_auth_header(header_bytes):
         )
 
 
-class BaseFederationServlet(object):
+class BaseFederationServlet:
     """Abstract base class for federation servlet classes.
 
     The servlet object should have a PATH attribute which takes the form of a regexp to
diff --git a/synapse/groups/attestations.py b/synapse/groups/attestations.py
index e674bf44a2..a86b3debc5 100644
--- a/synapse/groups/attestations.py
+++ b/synapse/groups/attestations.py
@@ -60,7 +60,7 @@ DEFAULT_ATTESTATION_JITTER = (0.9, 1.3)
 UPDATE_ATTESTATION_TIME_MS = 1 * 24 * 60 * 60 * 1000
 
 
-class GroupAttestationSigning(object):
+class GroupAttestationSigning:
     """Creates and verifies group attestations.
     """
 
@@ -124,7 +124,7 @@ class GroupAttestationSigning(object):
         )
 
 
-class GroupAttestionRenewer(object):
+class GroupAttestionRenewer:
     """Responsible for sending and receiving attestation updates.
     """
 
diff --git a/synapse/groups/groups_server.py b/synapse/groups/groups_server.py
index 8cb922ddc7..1dd20ee4e1 100644
--- a/synapse/groups/groups_server.py
+++ b/synapse/groups/groups_server.py
@@ -32,7 +32,7 @@ logger = logging.getLogger(__name__)
 # TODO: Flairs
 
 
-class GroupsServerWorkerHandler(object):
+class GroupsServerWorkerHandler:
     def __init__(self, hs):
         self.hs = hs
         self.store = hs.get_datastore()
diff --git a/synapse/handlers/__init__.py b/synapse/handlers/__init__.py
index 2dd183018a..286f0054be 100644
--- a/synapse/handlers/__init__.py
+++ b/synapse/handlers/__init__.py
@@ -20,7 +20,7 @@ from .identity import IdentityHandler
 from .search import SearchHandler
 
 
-class Handlers(object):
+class Handlers:
 
     """ Deprecated. A collection of handlers.
 
diff --git a/synapse/handlers/_base.py b/synapse/handlers/_base.py
index ba2bf99800..0206320e96 100644
--- a/synapse/handlers/_base.py
+++ b/synapse/handlers/_base.py
@@ -25,7 +25,7 @@ from synapse.types import UserID
 logger = logging.getLogger(__name__)
 
 
-class BaseHandler(object):
+class BaseHandler:
     """
     Common base class for the event handlers.
     """
diff --git a/synapse/handlers/account_data.py b/synapse/handlers/account_data.py
index a8d3fbc6de..9112a0ab86 100644
--- a/synapse/handlers/account_data.py
+++ b/synapse/handlers/account_data.py
@@ -14,7 +14,7 @@
 # limitations under the License.
 
 
-class AccountDataEventSource(object):
+class AccountDataEventSource:
     def __init__(self, hs):
         self.store = hs.get_datastore()
 
diff --git a/synapse/handlers/account_validity.py b/synapse/handlers/account_validity.py
index b865bf5b48..4caf6d591a 100644
--- a/synapse/handlers/account_validity.py
+++ b/synapse/handlers/account_validity.py
@@ -29,7 +29,7 @@ from synapse.util import stringutils
 logger = logging.getLogger(__name__)
 
 
-class AccountValidityHandler(object):
+class AccountValidityHandler:
     def __init__(self, hs):
         self.hs = hs
         self.config = hs.config
diff --git a/synapse/handlers/acme.py b/synapse/handlers/acme.py
index 7666d3abcd..8476256a59 100644
--- a/synapse/handlers/acme.py
+++ b/synapse/handlers/acme.py
@@ -34,7 +34,7 @@ solutions, please read https://github.com/matrix-org/synapse/blob/master/docs/AC
 --------------------------------------------------------------------------------"""
 
 
-class AcmeHandler(object):
+class AcmeHandler:
     def __init__(self, hs):
         self.hs = hs
         self.reactor = hs.get_reactor()
diff --git a/synapse/handlers/acme_issuing_service.py b/synapse/handlers/acme_issuing_service.py
index e1d4224e74..69650ff221 100644
--- a/synapse/handlers/acme_issuing_service.py
+++ b/synapse/handlers/acme_issuing_service.py
@@ -78,7 +78,7 @@ def create_issuing_service(reactor, acme_url, account_key_file, well_known_resou
 
 @attr.s
 @implementer(ICertificateStore)
-class ErsatzStore(object):
+class ErsatzStore:
     """
     A store that only stores in memory.
     """
diff --git a/synapse/handlers/admin.py b/synapse/handlers/admin.py
index 506bb2b275..918d0e037c 100644
--- a/synapse/handlers/admin.py
+++ b/synapse/handlers/admin.py
@@ -197,7 +197,7 @@ class AdminHandler(BaseHandler):
         return writer.finished()
 
 
-class ExfiltrationWriter(object):
+class ExfiltrationWriter:
     """Interface used to specify how to write exported data.
     """
 
diff --git a/synapse/handlers/appservice.py b/synapse/handlers/appservice.py
index c9044a5019..9d4e87dad6 100644
--- a/synapse/handlers/appservice.py
+++ b/synapse/handlers/appservice.py
@@ -34,7 +34,7 @@ logger = logging.getLogger(__name__)
 events_processed_counter = Counter("synapse_handlers_appservice_events_processed", "")
 
 
-class ApplicationServicesHandler(object):
+class ApplicationServicesHandler:
     def __init__(self, hs):
         self.store = hs.get_datastore()
         self.is_mine_id = hs.is_mine_id
diff --git a/synapse/handlers/auth.py b/synapse/handlers/auth.py
index f0b0a4d76a..90189869cc 100644
--- a/synapse/handlers/auth.py
+++ b/synapse/handlers/auth.py
@@ -1236,7 +1236,7 @@ class AuthHandler(BaseHandler):
 
 
 @attr.s
-class MacaroonGenerator(object):
+class MacaroonGenerator:
 
     hs = attr.ib()
 
diff --git a/synapse/handlers/device.py b/synapse/handlers/device.py
index ee4666337a..643d71a710 100644
--- a/synapse/handlers/device.py
+++ b/synapse/handlers/device.py
@@ -497,7 +497,7 @@ def _update_device_from_client_ips(device, client_ips):
     device.update({"last_seen_ts": ip.get("last_seen"), "last_seen_ip": ip.get("ip")})
 
 
-class DeviceListUpdater(object):
+class DeviceListUpdater:
     "Handles incoming device list updates from federation and updates the DB"
 
     def __init__(self, hs, device_handler):
diff --git a/synapse/handlers/devicemessage.py b/synapse/handlers/devicemessage.py
index dcb4c82244..64ef7f63ab 100644
--- a/synapse/handlers/devicemessage.py
+++ b/synapse/handlers/devicemessage.py
@@ -31,7 +31,7 @@ from synapse.util.stringutils import random_string
 logger = logging.getLogger(__name__)
 
 
-class DeviceMessageHandler(object):
+class DeviceMessageHandler:
     def __init__(self, hs):
         """
         Args:
diff --git a/synapse/handlers/e2e_keys.py b/synapse/handlers/e2e_keys.py
index dfd1c78549..d629c7c16c 100644
--- a/synapse/handlers/e2e_keys.py
+++ b/synapse/handlers/e2e_keys.py
@@ -43,7 +43,7 @@ from synapse.util.retryutils import NotRetryingDestination
 logger = logging.getLogger(__name__)
 
 
-class E2eKeysHandler(object):
+class E2eKeysHandler:
     def __init__(self, hs):
         self.store = hs.get_datastore()
         self.federation = hs.get_federation_client()
@@ -1212,7 +1212,7 @@ class SignatureListItem:
     signature = attr.ib()
 
 
-class SigningKeyEduUpdater(object):
+class SigningKeyEduUpdater:
     """Handles incoming signing key updates from federation and updates the DB"""
 
     def __init__(self, hs, e2e_keys_handler):
diff --git a/synapse/handlers/e2e_room_keys.py b/synapse/handlers/e2e_room_keys.py
index 0bb983dc28..f01b090772 100644
--- a/synapse/handlers/e2e_room_keys.py
+++ b/synapse/handlers/e2e_room_keys.py
@@ -29,7 +29,7 @@ from synapse.util.async_helpers import Linearizer
 logger = logging.getLogger(__name__)
 
 
-class E2eRoomKeysHandler(object):
+class E2eRoomKeysHandler:
     """
     Implements an optional realtime backup mechanism for encrypted E2E megolm room keys.
     This gives a way for users to store and recover their megolm keys if they lose all
diff --git a/synapse/handlers/groups_local.py b/synapse/handlers/groups_local.py
index 0e2656ccb3..44df567983 100644
--- a/synapse/handlers/groups_local.py
+++ b/synapse/handlers/groups_local.py
@@ -52,7 +52,7 @@ def _create_rerouter(func_name):
     return f
 
 
-class GroupsLocalWorkerHandler(object):
+class GroupsLocalWorkerHandler:
     def __init__(self, hs):
         self.hs = hs
         self.store = hs.get_datastore()
diff --git a/synapse/handlers/message.py b/synapse/handlers/message.py
index 72bb638167..8a7b4916cd 100644
--- a/synapse/handlers/message.py
+++ b/synapse/handlers/message.py
@@ -64,7 +64,7 @@ if TYPE_CHECKING:
 logger = logging.getLogger(__name__)
 
 
-class MessageHandler(object):
+class MessageHandler:
     """Contains some read only APIs to get state about a room
     """
 
@@ -361,7 +361,7 @@ class MessageHandler(object):
 _DUMMY_EVENT_ROOM_EXCLUSION_EXPIRY = 7 * 24 * 60 * 60 * 1000
 
 
-class EventCreationHandler(object):
+class EventCreationHandler:
     def __init__(self, hs: "HomeServer"):
         self.hs = hs
         self.auth = hs.get_auth()
diff --git a/synapse/handlers/pagination.py b/synapse/handlers/pagination.py
index 63d7edff87..34ed0e2921 100644
--- a/synapse/handlers/pagination.py
+++ b/synapse/handlers/pagination.py
@@ -37,7 +37,7 @@ if TYPE_CHECKING:
 logger = logging.getLogger(__name__)
 
 
-class PurgeStatus(object):
+class PurgeStatus:
     """Object tracking the status of a purge request
 
     This class contains information on the progress of a purge request, for
@@ -65,7 +65,7 @@ class PurgeStatus(object):
         return {"status": PurgeStatus.STATUS_TEXT[self.status]}
 
 
-class PaginationHandler(object):
+class PaginationHandler:
     """Handles pagination and purge history requests.
 
     These are in the same handler due to the fact we need to block clients
diff --git a/synapse/handlers/password_policy.py b/synapse/handlers/password_policy.py
index d06b110269..88e2f87200 100644
--- a/synapse/handlers/password_policy.py
+++ b/synapse/handlers/password_policy.py
@@ -22,7 +22,7 @@ from synapse.api.errors import Codes, PasswordRefusedError
 logger = logging.getLogger(__name__)
 
 
-class PasswordPolicyHandler(object):
+class PasswordPolicyHandler:
     def __init__(self, hs):
         self.policy = hs.config.password_policy
         self.enabled = hs.config.password_policy_enabled
diff --git a/synapse/handlers/presence.py b/synapse/handlers/presence.py
index 1846068150..91a3aec1cc 100644
--- a/synapse/handlers/presence.py
+++ b/synapse/handlers/presence.py
@@ -1010,7 +1010,7 @@ def format_user_presence_state(state, now, include_user_id=True):
     return content
 
 
-class PresenceEventSource(object):
+class PresenceEventSource:
     def __init__(self, hs):
         # We can't call get_presence_handler here because there's a cycle:
         #
diff --git a/synapse/handlers/receipts.py b/synapse/handlers/receipts.py
index f922d8a545..2cc6c2eb68 100644
--- a/synapse/handlers/receipts.py
+++ b/synapse/handlers/receipts.py
@@ -123,7 +123,7 @@ class ReceiptsHandler(BaseHandler):
         await self.federation.send_read_receipt(receipt)
 
 
-class ReceiptEventSource(object):
+class ReceiptEventSource:
     def __init__(self, hs):
         self.store = hs.get_datastore()
 
diff --git a/synapse/handlers/room.py b/synapse/handlers/room.py
index 9d5b1828df..a29305f655 100644
--- a/synapse/handlers/room.py
+++ b/synapse/handlers/room.py
@@ -974,7 +974,7 @@ class RoomCreationHandler(BaseHandler):
         raise StoreError(500, "Couldn't generate a room ID.")
 
 
-class RoomContextHandler(object):
+class RoomContextHandler:
     def __init__(self, hs: "HomeServer"):
         self.hs = hs
         self.store = hs.get_datastore()
@@ -1084,7 +1084,7 @@ class RoomContextHandler(object):
         return results
 
 
-class RoomEventSource(object):
+class RoomEventSource:
     def __init__(self, hs: "HomeServer"):
         self.store = hs.get_datastore()
 
@@ -1146,7 +1146,7 @@ class RoomEventSource(object):
         return self.store.get_room_events_max_id(room_id)
 
 
-class RoomShutdownHandler(object):
+class RoomShutdownHandler:
 
     DEFAULT_MESSAGE = (
         "Sharing illegal content on this server is not permitted and rooms in"
diff --git a/synapse/handlers/room_member.py b/synapse/handlers/room_member.py
index a7962b0ada..32b7e323fa 100644
--- a/synapse/handlers/room_member.py
+++ b/synapse/handlers/room_member.py
@@ -51,7 +51,7 @@ if TYPE_CHECKING:
 logger = logging.getLogger(__name__)
 
 
-class RoomMemberHandler(object):
+class RoomMemberHandler:
     # TODO(paul): This handler currently contains a messy conflation of
     #   low-level API that works on UserID objects and so on, and REST-level
     #   API that takes ID strings and returns pagination chunks. These concerns
diff --git a/synapse/handlers/saml_handler.py b/synapse/handlers/saml_handler.py
index b426199aa6..66b063f991 100644
--- a/synapse/handlers/saml_handler.py
+++ b/synapse/handlers/saml_handler.py
@@ -360,12 +360,12 @@ MXID_MAPPER_MAP = {
 
 
 @attr.s
-class SamlConfig(object):
+class SamlConfig:
     mxid_source_attribute = attr.ib()
     mxid_mapper = attr.ib()
 
 
-class DefaultSamlMappingProvider(object):
+class DefaultSamlMappingProvider:
     __version__ = "0.0.1"
 
     def __init__(self, parsed_config: SamlConfig, module_api: ModuleApi):
diff --git a/synapse/handlers/state_deltas.py b/synapse/handlers/state_deltas.py
index 8590c1eff4..7a4ae0727a 100644
--- a/synapse/handlers/state_deltas.py
+++ b/synapse/handlers/state_deltas.py
@@ -18,7 +18,7 @@ import logging
 logger = logging.getLogger(__name__)
 
 
-class StateDeltasHandler(object):
+class StateDeltasHandler:
     def __init__(self, hs):
         self.store = hs.get_datastore()
 
diff --git a/synapse/handlers/sync.py b/synapse/handlers/sync.py
index 8728403e62..e2ddb628ff 100644
--- a/synapse/handlers/sync.py
+++ b/synapse/handlers/sync.py
@@ -246,7 +246,7 @@ class SyncResult:
     __bool__ = __nonzero__  # python3
 
 
-class SyncHandler(object):
+class SyncHandler:
     def __init__(self, hs: "HomeServer"):
         self.hs_config = hs.config
         self.store = hs.get_datastore()
@@ -2075,7 +2075,7 @@ class SyncResultBuilder:
 
 
 @attr.s
-class RoomSyncResultBuilder(object):
+class RoomSyncResultBuilder:
     """Stores information needed to create either a `JoinedSyncResult` or
     `ArchivedSyncResult`.
 
diff --git a/synapse/handlers/typing.py b/synapse/handlers/typing.py
index 1d828bd7be..3cbfc2d780 100644
--- a/synapse/handlers/typing.py
+++ b/synapse/handlers/typing.py
@@ -412,7 +412,7 @@ class TypingWriterHandler(FollowerTypingHandler):
         raise Exception("Typing writer instance got typing info over replication")
 
 
-class TypingNotificationEventSource(object):
+class TypingNotificationEventSource:
     def __init__(self, hs):
         self.hs = hs
         self.clock = hs.get_clock()
diff --git a/synapse/http/client.py b/synapse/http/client.py
index dad01a8e56..13fcab3378 100644
--- a/synapse/http/client.py
+++ b/synapse/http/client.py
@@ -86,7 +86,7 @@ def _make_scheduler(reactor):
     return _scheduler
 
 
-class IPBlacklistingResolver(object):
+class IPBlacklistingResolver:
     """
     A proxy for reactor.nameResolver which only produces non-blacklisted IP
     addresses, preventing DNS rebinding attacks on URL preview.
@@ -133,7 +133,7 @@ class IPBlacklistingResolver(object):
             r.resolutionComplete()
 
         @provider(IResolutionReceiver)
-        class EndpointReceiver(object):
+        class EndpointReceiver:
             @staticmethod
             def resolutionBegan(resolutionInProgress):
                 pass
@@ -192,7 +192,7 @@ class BlacklistingAgentWrapper(Agent):
         )
 
 
-class SimpleHttpClient(object):
+class SimpleHttpClient:
     """
     A simple, no-frills HTTP client with methods that wrap up common ways of
     using HTTP in Matrix
@@ -244,7 +244,7 @@ class SimpleHttpClient(object):
             )
 
             @implementer(IReactorPluggableNameResolver)
-            class Reactor(object):
+            class Reactor:
                 def __getattr__(_self, attr):
                     if attr == "nameResolver":
                         return nameResolver
diff --git a/synapse/http/connectproxyclient.py b/synapse/http/connectproxyclient.py
index be7b2ceb8e..856e28454f 100644
--- a/synapse/http/connectproxyclient.py
+++ b/synapse/http/connectproxyclient.py
@@ -31,7 +31,7 @@ class ProxyConnectError(ConnectError):
 
 
 @implementer(IStreamClientEndpoint)
-class HTTPConnectProxyEndpoint(object):
+class HTTPConnectProxyEndpoint:
     """An Endpoint implementation which will send a CONNECT request to an http proxy
 
     Wraps an existing HostnameEndpoint for the proxy.
diff --git a/synapse/http/federation/matrix_federation_agent.py b/synapse/http/federation/matrix_federation_agent.py
index 782d39d4ca..83d6196d4a 100644
--- a/synapse/http/federation/matrix_federation_agent.py
+++ b/synapse/http/federation/matrix_federation_agent.py
@@ -36,7 +36,7 @@ logger = logging.getLogger(__name__)
 
 
 @implementer(IAgent)
-class MatrixFederationAgent(object):
+class MatrixFederationAgent:
     """An Agent-like thing which provides a `request` method which correctly
     handles resolving matrix server names when using matrix://. Handles standard
     https URIs as normal.
@@ -175,7 +175,7 @@ class MatrixFederationAgent(object):
 
 
 @implementer(IAgentEndpointFactory)
-class MatrixHostnameEndpointFactory(object):
+class MatrixHostnameEndpointFactory:
     """Factory for MatrixHostnameEndpoint for parsing to an Agent.
     """
 
@@ -198,7 +198,7 @@ class MatrixHostnameEndpointFactory(object):
 
 
 @implementer(IStreamClientEndpoint)
-class MatrixHostnameEndpoint(object):
+class MatrixHostnameEndpoint:
     """An endpoint that resolves matrix:// URLs using Matrix server name
     resolution (i.e. via SRV). Does not check for well-known delegation.
 
diff --git a/synapse/http/federation/srv_resolver.py b/synapse/http/federation/srv_resolver.py
index 2ede90a9b1..d9620032d2 100644
--- a/synapse/http/federation/srv_resolver.py
+++ b/synapse/http/federation/srv_resolver.py
@@ -33,7 +33,7 @@ SERVER_CACHE = {}
 
 
 @attr.s(slots=True, frozen=True)
-class Server(object):
+class Server:
     """
     Our record of an individual server which can be tried to reach a destination.
 
@@ -96,7 +96,7 @@ def _sort_server_list(server_list):
     return results
 
 
-class SrvResolver(object):
+class SrvResolver:
     """Interface to the dns client to do SRV lookups, with result caching.
 
     The default resolver in twisted.names doesn't do any caching (it has a CacheResolver,
diff --git a/synapse/http/federation/well_known_resolver.py b/synapse/http/federation/well_known_resolver.py
index cdb6bec56e..e6f067ca29 100644
--- a/synapse/http/federation/well_known_resolver.py
+++ b/synapse/http/federation/well_known_resolver.py
@@ -71,11 +71,11 @@ _had_valid_well_known_cache = TTLCache("had-valid-well-known")
 
 
 @attr.s(slots=True, frozen=True)
-class WellKnownLookupResult(object):
+class WellKnownLookupResult:
     delegated_server = attr.ib()
 
 
-class WellKnownResolver(object):
+class WellKnownResolver:
     """Handles well-known lookups for matrix servers.
     """
 
diff --git a/synapse/http/matrixfederationclient.py b/synapse/http/matrixfederationclient.py
index 738be43f46..775fad3be4 100644
--- a/synapse/http/matrixfederationclient.py
+++ b/synapse/http/matrixfederationclient.py
@@ -76,7 +76,7 @@ _next_id = 1
 
 
 @attr.s(frozen=True)
-class MatrixFederationRequest(object):
+class MatrixFederationRequest:
     method = attr.ib()
     """HTTP method
     :type: str
@@ -203,7 +203,7 @@ async def _handle_json_response(
     return body
 
 
-class MatrixFederationHttpClient(object):
+class MatrixFederationHttpClient:
     """HTTP client used to talk to other homeservers over the federation
     protocol. Send client certificates and signs requests.
 
@@ -226,7 +226,7 @@ class MatrixFederationHttpClient(object):
         )
 
         @implementer(IReactorPluggableNameResolver)
-        class Reactor(object):
+        class Reactor:
             def __getattr__(_self, attr):
                 if attr == "nameResolver":
                     return nameResolver
diff --git a/synapse/http/request_metrics.py b/synapse/http/request_metrics.py
index b58ae3d9db..cd94e789e8 100644
--- a/synapse/http/request_metrics.py
+++ b/synapse/http/request_metrics.py
@@ -145,7 +145,7 @@ LaterGauge(
 )
 
 
-class RequestMetrics(object):
+class RequestMetrics:
     def start(self, time_sec, name, method):
         self.start = time_sec
         self.start_context = current_context()
diff --git a/synapse/http/server.py b/synapse/http/server.py
index 8d791bd2ca..996a31a9ec 100644
--- a/synapse/http/server.py
+++ b/synapse/http/server.py
@@ -174,7 +174,7 @@ def wrap_async_request_handler(h):
     return preserve_fn(wrapped_async_request_handler)
 
 
-class HttpServer(object):
+class HttpServer:
     """ Interface for registering callbacks on a HTTP server
     """
 
diff --git a/synapse/http/servlet.py b/synapse/http/servlet.py
index 53acba56cb..fd90ba7828 100644
--- a/synapse/http/servlet.py
+++ b/synapse/http/servlet.py
@@ -256,7 +256,7 @@ def assert_params_in_dict(body, required):
         raise SynapseError(400, "Missing params: %r" % absent, Codes.MISSING_PARAM)
 
 
-class RestServlet(object):
+class RestServlet:
 
     """ A Synapse REST Servlet.
 
diff --git a/synapse/logging/_structured.py b/synapse/logging/_structured.py
index 7372450b45..144506c8f2 100644
--- a/synapse/logging/_structured.py
+++ b/synapse/logging/_structured.py
@@ -55,7 +55,7 @@ def stdlib_log_level_to_twisted(level: str) -> LogLevel:
 
 @attr.s
 @implementer(ILogObserver)
-class LogContextObserver(object):
+class LogContextObserver:
     """
     An ILogObserver which adds Synapse-specific log context information.
 
@@ -169,7 +169,7 @@ class OutputPipeType(Values):
 
 
 @attr.s
-class DrainConfiguration(object):
+class DrainConfiguration:
     name = attr.ib()
     type = attr.ib()
     location = attr.ib()
@@ -177,7 +177,7 @@ class DrainConfiguration(object):
 
 
 @attr.s
-class NetworkJSONTerseOptions(object):
+class NetworkJSONTerseOptions:
     maximum_buffer = attr.ib(type=int)
 
 
diff --git a/synapse/logging/_terse_json.py b/synapse/logging/_terse_json.py
index c0b9384189..1b8916cfa2 100644
--- a/synapse/logging/_terse_json.py
+++ b/synapse/logging/_terse_json.py
@@ -152,7 +152,7 @@ def TerseJSONToConsoleLogObserver(outFile: IO[str], metadata: dict) -> FileLogOb
 
 @attr.s
 @implementer(IPushProducer)
-class LogProducer(object):
+class LogProducer:
     """
     An IPushProducer that writes logs from its buffer to its transport when it
     is resumed.
@@ -190,7 +190,7 @@ class LogProducer(object):
 
 @attr.s
 @implementer(ILogObserver)
-class TerseJSONToTCPLogObserver(object):
+class TerseJSONToTCPLogObserver:
     """
     An IObserver that writes JSON logs to a TCP target.
 
diff --git a/synapse/logging/context.py b/synapse/logging/context.py
index cbeeb870cb..22598e02d2 100644
--- a/synapse/logging/context.py
+++ b/synapse/logging/context.py
@@ -74,7 +74,7 @@ except Exception:
 get_thread_id = threading.get_ident
 
 
-class ContextResourceUsage(object):
+class ContextResourceUsage:
     """Object for tracking the resources used by a log context
 
     Attributes:
@@ -179,7 +179,7 @@ class ContextResourceUsage(object):
 LoggingContextOrSentinel = Union["LoggingContext", "_Sentinel"]
 
 
-class _Sentinel(object):
+class _Sentinel:
     """Sentinel to represent the root context"""
 
     __slots__ = ["previous_context", "finished", "request", "scope", "tag"]
@@ -226,7 +226,7 @@ class _Sentinel(object):
 SENTINEL_CONTEXT = _Sentinel()
 
 
-class LoggingContext(object):
+class LoggingContext:
     """Additional context for log formatting. Contexts are scoped within a
     "with" block.
 
diff --git a/synapse/logging/opentracing.py b/synapse/logging/opentracing.py
index d39ac62168..7df0aa197d 100644
--- a/synapse/logging/opentracing.py
+++ b/synapse/logging/opentracing.py
@@ -185,7 +185,7 @@ if TYPE_CHECKING:
 # Helper class
 
 
-class _DummyTagNames(object):
+class _DummyTagNames:
     """wrapper of opentracings tags. We need to have them if we
     want to reference them without opentracing around. Clearly they
     should never actually show up in a trace. `set_tags` overwrites
diff --git a/synapse/metrics/__init__.py b/synapse/metrics/__init__.py
index 6035672698..2643380d9e 100644
--- a/synapse/metrics/__init__.py
+++ b/synapse/metrics/__init__.py
@@ -51,7 +51,7 @@ all_gauges = {}  # type: Dict[str, Union[LaterGauge, InFlightGauge, BucketCollec
 HAVE_PROC_SELF_STAT = os.path.exists("/proc/self/stat")
 
 
-class RegistryProxy(object):
+class RegistryProxy:
     @staticmethod
     def collect():
         for metric in REGISTRY.collect():
@@ -60,7 +60,7 @@ class RegistryProxy(object):
 
 
 @attr.s(hash=True)
-class LaterGauge(object):
+class LaterGauge:
 
     name = attr.ib(type=str)
     desc = attr.ib(type=str)
@@ -100,7 +100,7 @@ class LaterGauge(object):
         all_gauges[self.name] = self
 
 
-class InFlightGauge(object):
+class InFlightGauge:
     """Tracks number of things (e.g. requests, Measure blocks, etc) in flight
     at any given time.
 
@@ -206,7 +206,7 @@ class InFlightGauge(object):
 
 
 @attr.s(hash=True)
-class BucketCollector(object):
+class BucketCollector:
     """
     Like a Histogram, but allows buckets to be point-in-time instead of
     incrementally added to.
@@ -269,7 +269,7 @@ class BucketCollector(object):
 #
 
 
-class CPUMetrics(object):
+class CPUMetrics:
     def __init__(self):
         ticks_per_sec = 100
         try:
@@ -329,7 +329,7 @@ gc_time = Histogram(
 )
 
 
-class GCCounts(object):
+class GCCounts:
     def collect(self):
         cm = GaugeMetricFamily("python_gc_counts", "GC object counts", labels=["gen"])
         for n, m in enumerate(gc.get_count()):
@@ -347,7 +347,7 @@ if not running_on_pypy:
 #
 
 
-class PyPyGCStats(object):
+class PyPyGCStats:
     def collect(self):
 
         # @stats is a pretty-printer object with __str__() returning a nice table,
@@ -482,7 +482,7 @@ build_info.labels(
 last_ticked = time.time()
 
 
-class ReactorLastSeenMetric(object):
+class ReactorLastSeenMetric:
     def collect(self):
         cm = GaugeMetricFamily(
             "python_twisted_reactor_last_seen",
diff --git a/synapse/metrics/background_process_metrics.py b/synapse/metrics/background_process_metrics.py
index 4cd7932e5b..5b73463504 100644
--- a/synapse/metrics/background_process_metrics.py
+++ b/synapse/metrics/background_process_metrics.py
@@ -105,7 +105,7 @@ _background_processes_active_since_last_scrape = set()  # type: Set[_BackgroundP
 _bg_metrics_lock = threading.Lock()
 
 
-class _Collector(object):
+class _Collector:
     """A custom metrics collector for the background process metrics.
 
     Ensures that all of the metrics are up-to-date with any in-flight processes
@@ -140,7 +140,7 @@ class _Collector(object):
 REGISTRY.register(_Collector())
 
 
-class _BackgroundProcess(object):
+class _BackgroundProcess:
     def __init__(self, desc, ctx):
         self.desc = desc
         self._context = ctx
diff --git a/synapse/module_api/__init__.py b/synapse/module_api/__init__.py
index ae0e359a77..fcbd5378c4 100644
--- a/synapse/module_api/__init__.py
+++ b/synapse/module_api/__init__.py
@@ -31,7 +31,7 @@ __all__ = ["errors", "make_deferred_yieldable", "run_in_background", "ModuleApi"
 logger = logging.getLogger(__name__)
 
 
-class ModuleApi(object):
+class ModuleApi:
     """A proxy object that gets passed to various plugin modules so they
     can register new users etc if necessary.
     """
diff --git a/synapse/notifier.py b/synapse/notifier.py
index dfb096e589..b7f4041306 100644
--- a/synapse/notifier.py
+++ b/synapse/notifier.py
@@ -68,7 +68,7 @@ def count(func: Callable[[T], bool], it: Iterable[T]) -> int:
     return n
 
 
-class _NotificationListener(object):
+class _NotificationListener:
     """ This represents a single client connection to the events stream.
     The events stream handler will have yielded to the deferred, so to
     notify the handler it is sufficient to resolve the deferred.
@@ -80,7 +80,7 @@ class _NotificationListener(object):
         self.deferred = deferred
 
 
-class _NotifierUserStream(object):
+class _NotifierUserStream:
     """This represents a user connected to the event stream.
     It tracks the most recent stream token for that user.
     At a given point a user may have a number of streams listening for
@@ -168,7 +168,7 @@ class EventStreamResult(namedtuple("EventStreamResult", ("events", "tokens"))):
     __bool__ = __nonzero__  # python3
 
 
-class Notifier(object):
+class Notifier:
     """ This class is responsible for notifying any listeners when there are
     new events available for it.
 
diff --git a/synapse/push/action_generator.py b/synapse/push/action_generator.py
index 0d23142653..fabc9ba126 100644
--- a/synapse/push/action_generator.py
+++ b/synapse/push/action_generator.py
@@ -22,7 +22,7 @@ from .bulk_push_rule_evaluator import BulkPushRuleEvaluator
 logger = logging.getLogger(__name__)
 
 
-class ActionGenerator(object):
+class ActionGenerator:
     def __init__(self, hs):
         self.hs = hs
         self.clock = hs.get_clock()
diff --git a/synapse/push/bulk_push_rule_evaluator.py b/synapse/push/bulk_push_rule_evaluator.py
index e7fa02b78b..1bb8e346b9 100644
--- a/synapse/push/bulk_push_rule_evaluator.py
+++ b/synapse/push/bulk_push_rule_evaluator.py
@@ -95,7 +95,7 @@ def _should_count_as_unread(event: EventBase, context: EventContext) -> bool:
     return False
 
 
-class BulkPushRuleEvaluator(object):
+class BulkPushRuleEvaluator:
     """Calculates the outcome of push rules for an event for all users in the
     room at once.
     """
@@ -263,7 +263,7 @@ def _condition_checker(evaluator, conditions, uid, display_name, cache):
     return True
 
 
-class RulesForRoom(object):
+class RulesForRoom:
     """Caches push rules for users in a room.
 
     This efficiently handles users joining/leaving the room by not invalidating
diff --git a/synapse/push/emailpusher.py b/synapse/push/emailpusher.py
index 568c13eaea..b7ea4438e0 100644
--- a/synapse/push/emailpusher.py
+++ b/synapse/push/emailpusher.py
@@ -45,7 +45,7 @@ THROTTLE_RESET_AFTER_MS = 12 * 60 * 60 * 1000
 INCLUDE_ALL_UNREAD_NOTIFS = False
 
 
-class EmailPusher(object):
+class EmailPusher:
     """
     A pusher that sends email notifications about events (approximately)
     when they happen.
diff --git a/synapse/push/httppusher.py b/synapse/push/httppusher.py
index 4c469efb20..f21fa9b659 100644
--- a/synapse/push/httppusher.py
+++ b/synapse/push/httppusher.py
@@ -49,7 +49,7 @@ http_badges_failed_counter = Counter(
 )
 
 
-class HttpPusher(object):
+class HttpPusher:
     INITIAL_BACKOFF_SEC = 1  # in seconds because that's what Twisted takes
     MAX_BACKOFF_SEC = 60 * 60
 
diff --git a/synapse/push/mailer.py b/synapse/push/mailer.py
index c38e037281..6c57854018 100644
--- a/synapse/push/mailer.py
+++ b/synapse/push/mailer.py
@@ -92,7 +92,7 @@ ALLOWED_ATTRS = {
 # ALLOWED_SCHEMES = ["http", "https", "ftp", "mailto"]
 
 
-class Mailer(object):
+class Mailer:
     def __init__(self, hs, app_name, template_html, template_text):
         self.hs = hs
         self.template_html = template_html
diff --git a/synapse/push/push_rule_evaluator.py b/synapse/push/push_rule_evaluator.py
index 2d79ada189..709ace01e5 100644
--- a/synapse/push/push_rule_evaluator.py
+++ b/synapse/push/push_rule_evaluator.py
@@ -105,7 +105,7 @@ def tweaks_for_actions(actions: List[Union[str, Dict]]) -> Dict[str, Any]:
     return tweaks
 
 
-class PushRuleEvaluatorForEvent(object):
+class PushRuleEvaluatorForEvent:
     def __init__(
         self,
         event: EventBase,
diff --git a/synapse/push/pusher.py b/synapse/push/pusher.py
index f626797133..2a52e226e3 100644
--- a/synapse/push/pusher.py
+++ b/synapse/push/pusher.py
@@ -23,7 +23,7 @@ from .httppusher import HttpPusher
 logger = logging.getLogger(__name__)
 
 
-class PusherFactory(object):
+class PusherFactory:
     def __init__(self, hs):
         self.hs = hs
         self.config = hs.config
diff --git a/synapse/replication/http/_base.py b/synapse/replication/http/_base.py
index 6a28c2db9d..ba16f22c91 100644
--- a/synapse/replication/http/_base.py
+++ b/synapse/replication/http/_base.py
@@ -33,7 +33,7 @@ from synapse.util.stringutils import random_string
 logger = logging.getLogger(__name__)
 
 
-class ReplicationEndpoint(object):
+class ReplicationEndpoint:
     """Helper base class for defining new replication HTTP endpoints.
 
     This creates an endpoint under `/_synapse/replication/:NAME/:PATH_ARGS..`
diff --git a/synapse/replication/slave/storage/_slaved_id_tracker.py b/synapse/replication/slave/storage/_slaved_id_tracker.py
index 047f2c50f7..eb74903d68 100644
--- a/synapse/replication/slave/storage/_slaved_id_tracker.py
+++ b/synapse/replication/slave/storage/_slaved_id_tracker.py
@@ -16,7 +16,7 @@
 from synapse.storage.util.id_generators import _load_current_id
 
 
-class SlavedIdTracker(object):
+class SlavedIdTracker:
     def __init__(self, db_conn, table, column, extra_tables=[], step=1):
         self.step = step
         self._current = _load_current_id(db_conn, table, column, step)
diff --git a/synapse/replication/tcp/protocol.py b/synapse/replication/tcp/protocol.py
index 0350923898..0b0d204e64 100644
--- a/synapse/replication/tcp/protocol.py
+++ b/synapse/replication/tcp/protocol.py
@@ -113,7 +113,7 @@ PING_TIMEOUT_MULTIPLIER = 5
 PING_TIMEOUT_MS = PING_TIME * PING_TIMEOUT_MULTIPLIER
 
 
-class ConnectionStates(object):
+class ConnectionStates:
     CONNECTING = "connecting"
     ESTABLISHED = "established"
     PAUSED = "paused"
diff --git a/synapse/replication/tcp/resource.py b/synapse/replication/tcp/resource.py
index 41569305df..04d894fb3d 100644
--- a/synapse/replication/tcp/resource.py
+++ b/synapse/replication/tcp/resource.py
@@ -58,7 +58,7 @@ class ReplicationStreamProtocolFactory(Factory):
         )
 
 
-class ReplicationStreamer(object):
+class ReplicationStreamer:
     """Handles replication connections.
 
     This needs to be poked when new replication data may be available. When new
diff --git a/synapse/replication/tcp/streams/_base.py b/synapse/replication/tcp/streams/_base.py
index 8c3caf30c9..682d47f402 100644
--- a/synapse/replication/tcp/streams/_base.py
+++ b/synapse/replication/tcp/streams/_base.py
@@ -79,7 +79,7 @@ StreamUpdateResult = Tuple[List[Tuple[Token, StreamRow]], Token, bool]
 UpdateFunction = Callable[[str, Token, Token, int], Awaitable[StreamUpdateResult]]
 
 
-class Stream(object):
+class Stream:
     """Base class for the streams.
 
     Provides a `get_updates()` function that returns new updates since the last
diff --git a/synapse/replication/tcp/streams/events.py b/synapse/replication/tcp/streams/events.py
index 16c63ff4ec..f929fc3954 100644
--- a/synapse/replication/tcp/streams/events.py
+++ b/synapse/replication/tcp/streams/events.py
@@ -49,14 +49,14 @@ data part are:
 
 
 @attr.s(slots=True, frozen=True)
-class EventsStreamRow(object):
+class EventsStreamRow:
     """A parsed row from the events replication stream"""
 
     type = attr.ib()  # str: the TypeId of one of the *EventsStreamRows
     data = attr.ib()  # BaseEventsStreamRow
 
 
-class BaseEventsStreamRow(object):
+class BaseEventsStreamRow:
     """Base class for rows to be sent in the events stream.
 
     Specifies how to identify, serialize and deserialize the different types.
diff --git a/synapse/rest/client/transactions.py b/synapse/rest/client/transactions.py
index 6da71dc46f..7be5c0fb88 100644
--- a/synapse/rest/client/transactions.py
+++ b/synapse/rest/client/transactions.py
@@ -25,7 +25,7 @@ logger = logging.getLogger(__name__)
 CLEANUP_PERIOD_MS = 1000 * 60 * 30  # 30 mins
 
 
-class HttpTransactionCache(object):
+class HttpTransactionCache:
     def __init__(self, hs):
         self.hs = hs
         self.auth = self.hs.get_auth()
diff --git a/synapse/rest/client/v2_alpha/register.py b/synapse/rest/client/v2_alpha/register.py
index 51372cdb5e..b6b90a8b30 100644
--- a/synapse/rest/client/v2_alpha/register.py
+++ b/synapse/rest/client/v2_alpha/register.py
@@ -658,7 +658,7 @@ class RegisterRestServlet(RestServlet):
             (object) params: registration parameters, from which we pull
                 device_id, initial_device_name and inhibit_login
         Returns:
-            (object) dictionary for response from /register
+             dictionary for response from /register
         """
         result = {"user_id": user_id, "home_server": self.hs.hostname}
         if not params.get("inhibit_login", False):
diff --git a/synapse/rest/media/v1/_base.py b/synapse/rest/media/v1/_base.py
index 20ddb9550b..6568e61829 100644
--- a/synapse/rest/media/v1/_base.py
+++ b/synapse/rest/media/v1/_base.py
@@ -235,7 +235,7 @@ async def respond_with_responder(
     finish_request(request)
 
 
-class Responder(object):
+class Responder:
     """Represents a response that can be streamed to the requester.
 
     Responder is a context manager which *must* be used, so that any resources
@@ -260,7 +260,7 @@ class Responder(object):
         pass
 
 
-class FileInfo(object):
+class FileInfo:
     """Details about a requested/uploaded file.
 
     Attributes:
diff --git a/synapse/rest/media/v1/filepath.py b/synapse/rest/media/v1/filepath.py
index e25c382c9c..d2826374a7 100644
--- a/synapse/rest/media/v1/filepath.py
+++ b/synapse/rest/media/v1/filepath.py
@@ -33,7 +33,7 @@ def _wrap_in_base_path(func):
     return _wrapped
 
 
-class MediaFilePaths(object):
+class MediaFilePaths:
     """Describes where files are stored on disk.
 
     Most of the functions have a `*_rel` variant which returns a file path that
diff --git a/synapse/rest/media/v1/media_repository.py b/synapse/rest/media/v1/media_repository.py
index 6fb4039e98..9a1b7779f7 100644
--- a/synapse/rest/media/v1/media_repository.py
+++ b/synapse/rest/media/v1/media_repository.py
@@ -62,7 +62,7 @@ logger = logging.getLogger(__name__)
 UPDATE_RECENTLY_ACCESSED_TS = 60 * 1000
 
 
-class MediaRepository(object):
+class MediaRepository:
     def __init__(self, hs):
         self.hs = hs
         self.auth = hs.get_auth()
diff --git a/synapse/rest/media/v1/media_storage.py b/synapse/rest/media/v1/media_storage.py
index ab1fa705bf..3a352b5631 100644
--- a/synapse/rest/media/v1/media_storage.py
+++ b/synapse/rest/media/v1/media_storage.py
@@ -34,7 +34,7 @@ if TYPE_CHECKING:
 logger = logging.getLogger(__name__)
 
 
-class MediaStorage(object):
+class MediaStorage:
     """Responsible for storing/fetching files from local sources.
 
     Args:
diff --git a/synapse/rest/media/v1/thumbnailer.py b/synapse/rest/media/v1/thumbnailer.py
index 7126997134..d681bf7bf0 100644
--- a/synapse/rest/media/v1/thumbnailer.py
+++ b/synapse/rest/media/v1/thumbnailer.py
@@ -31,7 +31,7 @@ EXIF_TRANSPOSE_MAPPINGS = {
 }
 
 
-class Thumbnailer(object):
+class Thumbnailer:
 
     FORMATS = {"image/jpeg": "JPEG", "image/png": "PNG"}
 
diff --git a/synapse/rest/well_known.py b/synapse/rest/well_known.py
index e15e13b756..f591cc6c5c 100644
--- a/synapse/rest/well_known.py
+++ b/synapse/rest/well_known.py
@@ -23,7 +23,7 @@ from synapse.util import json_encoder
 logger = logging.getLogger(__name__)
 
 
-class WellKnownBuilder(object):
+class WellKnownBuilder:
     """Utility to construct the well-known response
 
     Args:
diff --git a/synapse/secrets.py b/synapse/secrets.py
index ff86950a54..fb6d90a3b7 100644
--- a/synapse/secrets.py
+++ b/synapse/secrets.py
@@ -37,7 +37,7 @@ else:
     import binascii
     import os
 
-    class Secrets(object):
+    class Secrets:
         def token_bytes(self, nbytes=32):
             return os.urandom(nbytes)
 
diff --git a/synapse/server_notices/consent_server_notices.py b/synapse/server_notices/consent_server_notices.py
index 089cfef0b3..3673e7f47e 100644
--- a/synapse/server_notices/consent_server_notices.py
+++ b/synapse/server_notices/consent_server_notices.py
@@ -23,7 +23,7 @@ from synapse.types import get_localpart_from_id
 logger = logging.getLogger(__name__)
 
 
-class ConsentServerNotices(object):
+class ConsentServerNotices:
     """Keeps track of whether we need to send users server_notices about
     privacy policy consent, and sends one if we do.
     """
diff --git a/synapse/server_notices/resource_limits_server_notices.py b/synapse/server_notices/resource_limits_server_notices.py
index c2faef6eab..2258d306d9 100644
--- a/synapse/server_notices/resource_limits_server_notices.py
+++ b/synapse/server_notices/resource_limits_server_notices.py
@@ -27,7 +27,7 @@ from synapse.server_notices.server_notices_manager import SERVER_NOTICE_ROOM_TAG
 logger = logging.getLogger(__name__)
 
 
-class ResourceLimitsServerNotices(object):
+class ResourceLimitsServerNotices:
     """ Keeps track of whether the server has reached it's resource limit and
     ensures that the client is kept up to date.
     """
diff --git a/synapse/server_notices/server_notices_manager.py b/synapse/server_notices/server_notices_manager.py
index ed96aa8571..0422d4c7ce 100644
--- a/synapse/server_notices/server_notices_manager.py
+++ b/synapse/server_notices/server_notices_manager.py
@@ -25,7 +25,7 @@ logger = logging.getLogger(__name__)
 SERVER_NOTICE_ROOM_TAG = "m.server_notice"
 
 
-class ServerNoticesManager(object):
+class ServerNoticesManager:
     def __init__(self, hs):
         """
 
diff --git a/synapse/server_notices/server_notices_sender.py b/synapse/server_notices/server_notices_sender.py
index a754f75db4..6870b67ca0 100644
--- a/synapse/server_notices/server_notices_sender.py
+++ b/synapse/server_notices/server_notices_sender.py
@@ -20,7 +20,7 @@ from synapse.server_notices.resource_limits_server_notices import (
 )
 
 
-class ServerNoticesSender(object):
+class ServerNoticesSender:
     """A centralised place which sends server notices automatically when
     Certain Events take place
     """
diff --git a/synapse/server_notices/worker_server_notices_sender.py b/synapse/server_notices/worker_server_notices_sender.py
index e9390b19da..9273e61895 100644
--- a/synapse/server_notices/worker_server_notices_sender.py
+++ b/synapse/server_notices/worker_server_notices_sender.py
@@ -14,7 +14,7 @@
 # limitations under the License.
 
 
-class WorkerServerNoticesSender(object):
+class WorkerServerNoticesSender:
     """Stub impl of ServerNoticesSender which does nothing"""
 
     def __init__(self, hs):
diff --git a/synapse/spam_checker_api/__init__.py b/synapse/spam_checker_api/__init__.py
index 9be92e2565..395ac5ab02 100644
--- a/synapse/spam_checker_api/__init__.py
+++ b/synapse/spam_checker_api/__init__.py
@@ -36,7 +36,7 @@ class RegistrationBehaviour(Enum):
     DENY = "deny"
 
 
-class SpamCheckerApi(object):
+class SpamCheckerApi:
     """A proxy object that gets passed to spam checkers so they can get
     access to rooms and other relevant information.
     """
diff --git a/synapse/state/__init__.py b/synapse/state/__init__.py
index 9bf2ec368f..c7e3015b5d 100644
--- a/synapse/state/__init__.py
+++ b/synapse/state/__init__.py
@@ -77,7 +77,7 @@ def _gen_state_id():
     return s
 
 
-class _StateCacheEntry(object):
+class _StateCacheEntry:
     __slots__ = ["state", "state_group", "state_id", "prev_group", "delta_ids"]
 
     def __init__(
@@ -113,7 +113,7 @@ class _StateCacheEntry(object):
         return len(self.state)
 
 
-class StateHandler(object):
+class StateHandler:
     """Fetches bits of state from the stores, and does state resolution
     where necessary
     """
@@ -462,7 +462,7 @@ class StateHandler(object):
         return {key: state_map[ev_id] for key, ev_id in new_state.items()}
 
 
-class StateResolutionHandler(object):
+class StateResolutionHandler:
     """Responsible for doing state conflict resolution.
 
     Note that the storage layer depends on this handler, so all functions must
@@ -679,7 +679,7 @@ def resolve_events_with_store(
 
 
 @attr.s
-class StateResolutionStore(object):
+class StateResolutionStore:
     """Interface that allows state resolution algorithms to access the database
     in well defined way.
 
diff --git a/synapse/storage/__init__.py b/synapse/storage/__init__.py
index 5ef3853559..8e5d78f6f7 100644
--- a/synapse/storage/__init__.py
+++ b/synapse/storage/__init__.py
@@ -37,7 +37,7 @@ from synapse.storage.state import StateGroupStorage
 __all__ = ["DataStores", "DataStore"]
 
 
-class Storage(object):
+class Storage:
     """The high level interfaces for talking to various storage layers.
     """
 
diff --git a/synapse/storage/background_updates.py b/synapse/storage/background_updates.py
index 67a89cd51a..810721ebe9 100644
--- a/synapse/storage/background_updates.py
+++ b/synapse/storage/background_updates.py
@@ -24,7 +24,7 @@ from . import engines
 logger = logging.getLogger(__name__)
 
 
-class BackgroundUpdatePerformance(object):
+class BackgroundUpdatePerformance:
     """Tracks the how long a background update is taking to update its items"""
 
     def __init__(self, name):
@@ -71,7 +71,7 @@ class BackgroundUpdatePerformance(object):
             return float(self.total_item_count) / float(self.total_duration_ms)
 
 
-class BackgroundUpdater(object):
+class BackgroundUpdater:
     """ Background updates are updates to the database that run in the
     background. Each update processes a batch of data at once. We attempt to
     limit the impact of each update by monitoring how long each batch takes to
diff --git a/synapse/storage/database.py b/synapse/storage/database.py
index 78ca6d8346..8be943f589 100644
--- a/synapse/storage/database.py
+++ b/synapse/storage/database.py
@@ -248,7 +248,7 @@ class LoggingTransaction:
         self.txn.close()
 
 
-class PerformanceCounters(object):
+class PerformanceCounters:
     def __init__(self):
         self.current_counters = {}
         self.previous_counters = {}
@@ -286,7 +286,7 @@ class PerformanceCounters(object):
 R = TypeVar("R")
 
 
-class DatabasePool(object):
+class DatabasePool:
     """Wraps a single physical database and connection pool.
 
     A single database may be used by multiple data stores.
diff --git a/synapse/storage/databases/__init__.py b/synapse/storage/databases/__init__.py
index 0ac854aee2..7f08bd8285 100644
--- a/synapse/storage/databases/__init__.py
+++ b/synapse/storage/databases/__init__.py
@@ -24,7 +24,7 @@ from synapse.storage.prepare_database import prepare_database
 logger = logging.getLogger(__name__)
 
 
-class Databases(object):
+class Databases:
     """The various databases.
 
     These are low level interfaces to physical databases.
diff --git a/synapse/storage/databases/main/roommember.py b/synapse/storage/databases/main/roommember.py
index c46f5cd524..91a8b43da3 100644
--- a/synapse/storage/databases/main/roommember.py
+++ b/synapse/storage/databases/main/roommember.py
@@ -999,7 +999,7 @@ class RoomMemberStore(RoomMemberWorkerStore, RoomMemberBackgroundUpdateStore):
         await self.db_pool.runInteraction("forget_membership", f)
 
 
-class _JoinedHostsCache(object):
+class _JoinedHostsCache:
     """Cache for joined hosts in a room that is optimised to handle updates
     via state deltas.
     """
diff --git a/synapse/storage/keys.py b/synapse/storage/keys.py
index 4769b21529..afd10f7bae 100644
--- a/synapse/storage/keys.py
+++ b/synapse/storage/keys.py
@@ -22,6 +22,6 @@ logger = logging.getLogger(__name__)
 
 
 @attr.s(slots=True, frozen=True)
-class FetchKeyResult(object):
+class FetchKeyResult:
     verify_key = attr.ib()  # VerifyKey: the key itself
     valid_until_ts = attr.ib()  # int: how long we can use this key for
diff --git a/synapse/storage/persist_events.py b/synapse/storage/persist_events.py
index f15b95e633..dbaeef91dd 100644
--- a/synapse/storage/persist_events.py
+++ b/synapse/storage/persist_events.py
@@ -69,7 +69,7 @@ stale_forward_extremities_counter = Histogram(
 )
 
 
-class _EventPeristenceQueue(object):
+class _EventPeristenceQueue:
     """Queues up events so that they can be persisted in bulk with only one
     concurrent transaction per room.
     """
@@ -172,7 +172,7 @@ class _EventPeristenceQueue(object):
             pass
 
 
-class EventsPersistenceStorage(object):
+class EventsPersistenceStorage:
     """High level interface for handling persisting newly received events.
 
     Takes care of batching up events by room, and calculating the necessary
diff --git a/synapse/storage/prepare_database.py b/synapse/storage/prepare_database.py
index 1c5f305132..964d8d9eb8 100644
--- a/synapse/storage/prepare_database.py
+++ b/synapse/storage/prepare_database.py
@@ -569,7 +569,7 @@ def _get_or_create_schema_state(txn, database_engine):
 
 
 @attr.s()
-class _DirectoryListing(object):
+class _DirectoryListing:
     """Helper class to store schema file name and the
     absolute path to it.
 
diff --git a/synapse/storage/purge_events.py b/synapse/storage/purge_events.py
index 79d9f06e2e..bfa0a9fd06 100644
--- a/synapse/storage/purge_events.py
+++ b/synapse/storage/purge_events.py
@@ -20,7 +20,7 @@ from typing import Set
 logger = logging.getLogger(__name__)
 
 
-class PurgeEventsStorage(object):
+class PurgeEventsStorage:
     """High level interface for purging rooms and event history.
     """
 
diff --git a/synapse/storage/relations.py b/synapse/storage/relations.py
index d471ec9860..d30e3f11e7 100644
--- a/synapse/storage/relations.py
+++ b/synapse/storage/relations.py
@@ -23,7 +23,7 @@ logger = logging.getLogger(__name__)
 
 
 @attr.s
-class PaginationChunk(object):
+class PaginationChunk:
     """Returned by relation pagination APIs.
 
     Attributes:
@@ -51,7 +51,7 @@ class PaginationChunk(object):
 
 
 @attr.s(frozen=True, slots=True)
-class RelationPaginationToken(object):
+class RelationPaginationToken:
     """Pagination token for relation pagination API.
 
     As the results are in topological order, we can use the
@@ -82,7 +82,7 @@ class RelationPaginationToken(object):
 
 
 @attr.s(frozen=True, slots=True)
-class AggregationPaginationToken(object):
+class AggregationPaginationToken:
     """Pagination token for relation aggregation pagination API.
 
     As the results are order by count and then MAX(stream_ordering) of the
diff --git a/synapse/storage/state.py b/synapse/storage/state.py
index 96a1b59d64..8f68d968f0 100644
--- a/synapse/storage/state.py
+++ b/synapse/storage/state.py
@@ -29,7 +29,7 @@ T = TypeVar("T")
 
 
 @attr.s(slots=True)
-class StateFilter(object):
+class StateFilter:
     """A filter used when querying for state.
 
     Attributes:
@@ -326,7 +326,7 @@ class StateFilter(object):
         return member_filter, non_member_filter
 
 
-class StateGroupStorage(object):
+class StateGroupStorage:
     """High level interface to fetching state for event.
     """
 
diff --git a/synapse/storage/util/id_generators.py b/synapse/storage/util/id_generators.py
index 9f3d23f0a5..76bc3afdfa 100644
--- a/synapse/storage/util/id_generators.py
+++ b/synapse/storage/util/id_generators.py
@@ -25,7 +25,7 @@ from synapse.storage.database import DatabasePool, LoggingTransaction
 from synapse.storage.util.sequence import PostgresSequenceGenerator
 
 
-class IdGenerator(object):
+class IdGenerator:
     def __init__(self, db_conn, table, column):
         self._lock = threading.Lock()
         self._next_id = _load_current_id(db_conn, table, column)
@@ -59,7 +59,7 @@ def _load_current_id(db_conn, table, column, step=1):
     return (max if step > 0 else min)(current_id, step)
 
 
-class StreamIdGenerator(object):
+class StreamIdGenerator:
     """Used to generate new stream ids when persisting events while keeping
     track of which transactions have been completed.
 
diff --git a/synapse/streams/config.py b/synapse/streams/config.py
index ca7c16ff65..d97dc4d101 100644
--- a/synapse/streams/config.py
+++ b/synapse/streams/config.py
@@ -25,7 +25,7 @@ logger = logging.getLogger(__name__)
 MAX_LIMIT = 1000
 
 
-class SourcePaginationConfig(object):
+class SourcePaginationConfig:
 
     """A configuration object which stores pagination parameters for a
     specific event source."""
@@ -45,7 +45,7 @@ class SourcePaginationConfig(object):
         )
 
 
-class PaginationConfig(object):
+class PaginationConfig:
 
     """A configuration object which stores pagination parameters."""
 
diff --git a/synapse/streams/events.py b/synapse/streams/events.py
index 7ab46f42bf..92fd5d489f 100644
--- a/synapse/streams/events.py
+++ b/synapse/streams/events.py
@@ -23,7 +23,7 @@ from synapse.handlers.typing import TypingNotificationEventSource
 from synapse.types import StreamToken
 
 
-class EventSources(object):
+class EventSources:
     SOURCE_TYPES = {
         "room": RoomEventSource,
         "presence": PresenceEventSource,
diff --git a/synapse/types.py b/synapse/types.py
index f8b9b03850..f7de48f148 100644
--- a/synapse/types.py
+++ b/synapse/types.py
@@ -529,7 +529,7 @@ class ThirdPartyInstanceID(
 
 
 @attr.s(slots=True)
-class ReadReceipt(object):
+class ReadReceipt:
     """Information about a read-receipt"""
 
     room_id = attr.ib()
diff --git a/synapse/util/__init__.py b/synapse/util/__init__.py
index b2a22dbd5c..3ad4b28fc7 100644
--- a/synapse/util/__init__.py
+++ b/synapse/util/__init__.py
@@ -46,7 +46,7 @@ def unwrapFirstError(failure):
 
 
 @attr.s
-class Clock(object):
+class Clock:
     """
     A Clock wraps a Twisted reactor and provides utilities on top of it.
 
diff --git a/synapse/util/async_helpers.py b/synapse/util/async_helpers.py
index dfefbd996d..bb57e27beb 100644
--- a/synapse/util/async_helpers.py
+++ b/synapse/util/async_helpers.py
@@ -36,7 +36,7 @@ from synapse.util import Clock, unwrapFirstError
 logger = logging.getLogger(__name__)
 
 
-class ObservableDeferred(object):
+class ObservableDeferred:
     """Wraps a deferred object so that we can add observer deferreds. These
     observer deferreds do not affect the callback chain of the original
     deferred.
@@ -188,7 +188,7 @@ def yieldable_gather_results(func, iter, *args, **kwargs):
     ).addErrback(unwrapFirstError)
 
 
-class Linearizer(object):
+class Linearizer:
     """Limits concurrent access to resources based on a key. Useful to ensure
     only a few things happen at a time on a given resource.
 
@@ -338,7 +338,7 @@ class Linearizer(object):
         return new_defer
 
 
-class ReadWriteLock(object):
+class ReadWriteLock:
     """An async read write lock.
 
     Example:
@@ -502,7 +502,7 @@ def timeout_deferred(deferred, timeout, reactor, on_timeout_cancel=None):
 
 
 @attr.s(slots=True, frozen=True)
-class DoneAwaitable(object):
+class DoneAwaitable:
     """Simple awaitable that returns the provided value.
     """
 
diff --git a/synapse/util/caches/__init__.py b/synapse/util/caches/__init__.py
index dd356bf156..237f588658 100644
--- a/synapse/util/caches/__init__.py
+++ b/synapse/util/caches/__init__.py
@@ -43,7 +43,7 @@ response_cache_total = Gauge("synapse_util_caches_response_cache:total", "", ["n
 
 
 @attr.s
-class CacheMetric(object):
+class CacheMetric:
 
     _cache = attr.ib()
     _cache_type = attr.ib(type=str)
diff --git a/synapse/util/caches/descriptors.py b/synapse/util/caches/descriptors.py
index 825810eb16..98b34f2223 100644
--- a/synapse/util/caches/descriptors.py
+++ b/synapse/util/caches/descriptors.py
@@ -64,7 +64,7 @@ cache_pending_metric = Gauge(
 _CacheSentinel = object()
 
 
-class CacheEntry(object):
+class CacheEntry:
     __slots__ = ["deferred", "callbacks", "invalidated"]
 
     def __init__(self, deferred, callbacks):
@@ -80,7 +80,7 @@ class CacheEntry(object):
             self.callbacks.clear()
 
 
-class Cache(object):
+class Cache:
     __slots__ = (
         "cache",
         "name",
@@ -288,7 +288,7 @@ class Cache(object):
         self._pending_deferred_cache.clear()
 
 
-class _CacheDescriptorBase(object):
+class _CacheDescriptorBase:
     def __init__(self, orig: _CachedFunction, num_args, cache_context=False):
         self.orig = orig
 
@@ -705,7 +705,7 @@ def cachedList(
 
     Example:
 
-        class Example(object):
+        class Example:
             @cached(num_args=2)
             def do_something(self, first_arg):
                 ...
diff --git a/synapse/util/caches/dictionary_cache.py b/synapse/util/caches/dictionary_cache.py
index 6834e6f3ae..8592b93689 100644
--- a/synapse/util/caches/dictionary_cache.py
+++ b/synapse/util/caches/dictionary_cache.py
@@ -40,7 +40,7 @@ class DictionaryEntry(namedtuple("DictionaryEntry", ("full", "known_absent", "va
         return len(self.value)
 
 
-class DictionaryCache(object):
+class DictionaryCache:
     """Caches key -> dictionary lookups, supporting caching partial dicts, i.e.
     fetching a subset of dictionary keys for a particular key.
     """
@@ -53,7 +53,7 @@ class DictionaryCache(object):
         self.thread = None
         # caches_by_name[name] = self.cache
 
-        class Sentinel(object):
+        class Sentinel:
             __slots__ = []
 
         self.sentinel = Sentinel()
diff --git a/synapse/util/caches/expiringcache.py b/synapse/util/caches/expiringcache.py
index 89a3420f92..e15f7ee698 100644
--- a/synapse/util/caches/expiringcache.py
+++ b/synapse/util/caches/expiringcache.py
@@ -26,7 +26,7 @@ logger = logging.getLogger(__name__)
 SENTINEL = object()
 
 
-class ExpiringCache(object):
+class ExpiringCache:
     def __init__(
         self,
         cache_name,
@@ -190,7 +190,7 @@ class ExpiringCache(object):
         return False
 
 
-class _CacheEntry(object):
+class _CacheEntry:
     __slots__ = ["time", "value"]
 
     def __init__(self, time, value):
diff --git a/synapse/util/caches/lrucache.py b/synapse/util/caches/lrucache.py
index df4ea5901d..4bc1a67b58 100644
--- a/synapse/util/caches/lrucache.py
+++ b/synapse/util/caches/lrucache.py
@@ -30,7 +30,7 @@ def enumerate_leaves(node, depth):
                 yield m
 
 
-class _Node(object):
+class _Node:
     __slots__ = ["prev_node", "next_node", "key", "value", "callbacks"]
 
     def __init__(self, prev_node, next_node, key, value, callbacks=set()):
@@ -41,7 +41,7 @@ class _Node(object):
         self.callbacks = callbacks
 
 
-class LruCache(object):
+class LruCache:
     """
     Least-recently-used cache.
     Supports del_multi only if cache_type=TreeCache
diff --git a/synapse/util/caches/response_cache.py b/synapse/util/caches/response_cache.py
index a6c60888e5..df1a721add 100644
--- a/synapse/util/caches/response_cache.py
+++ b/synapse/util/caches/response_cache.py
@@ -23,7 +23,7 @@ from synapse.util.caches import register_cache
 logger = logging.getLogger(__name__)
 
 
-class ResponseCache(object):
+class ResponseCache:
     """
     This caches a deferred response. Until the deferred completes it will be
     returned from the cache. This means that if the client retries the request
diff --git a/synapse/util/caches/treecache.py b/synapse/util/caches/treecache.py
index ecd9948e79..eb4d98f683 100644
--- a/synapse/util/caches/treecache.py
+++ b/synapse/util/caches/treecache.py
@@ -3,7 +3,7 @@ from typing import Dict
 SENTINEL = object()
 
 
-class TreeCache(object):
+class TreeCache:
     """
     Tree-based backing store for LruCache. Allows subtrees of data to be deleted
     efficiently.
@@ -89,7 +89,7 @@ def iterate_tree_cache_entry(d):
             yield d
 
 
-class _Entry(object):
+class _Entry:
     __slots__ = ["value"]
 
     def __init__(self, value):
diff --git a/synapse/util/caches/ttlcache.py b/synapse/util/caches/ttlcache.py
index 6437aa907e..3e180cafd3 100644
--- a/synapse/util/caches/ttlcache.py
+++ b/synapse/util/caches/ttlcache.py
@@ -26,7 +26,7 @@ logger = logging.getLogger(__name__)
 SENTINEL = object()
 
 
-class TTLCache(object):
+class TTLCache:
     """A key/value cache implementation where each entry has its own TTL"""
 
     def __init__(self, cache_name, timer=time.time):
@@ -154,7 +154,7 @@ class TTLCache(object):
 
 
 @attr.s(frozen=True, slots=True)
-class _CacheEntry(object):
+class _CacheEntry:
     """TTLCache entry"""
 
     # expiry_time is the first attribute, so that entries are sorted by expiry.
diff --git a/synapse/util/distributor.py b/synapse/util/distributor.py
index 22a857a306..a750261e77 100644
--- a/synapse/util/distributor.py
+++ b/synapse/util/distributor.py
@@ -34,7 +34,7 @@ def user_joined_room(distributor, user, room_id):
     distributor.fire("user_joined_room", user=user, room_id=room_id)
 
 
-class Distributor(object):
+class Distributor:
     """A central dispatch point for loosely-connected pieces of code to
     register, observe, and fire signals.
 
@@ -103,7 +103,7 @@ def maybeAwaitableDeferred(f, *args, **kw):
         return succeed(result)
 
 
-class Signal(object):
+class Signal:
     """A Signal is a dispatch point that stores a list of callables as
     observers of it.
 
diff --git a/synapse/util/file_consumer.py b/synapse/util/file_consumer.py
index 6a3f6177b1..733f5e26e6 100644
--- a/synapse/util/file_consumer.py
+++ b/synapse/util/file_consumer.py
@@ -20,7 +20,7 @@ from twisted.internet import threads
 from synapse.logging.context import make_deferred_yieldable, run_in_background
 
 
-class BackgroundFileConsumer(object):
+class BackgroundFileConsumer:
     """A consumer that writes to a file like object. Supports both push
     and pull producers
 
diff --git a/synapse/util/jsonobject.py b/synapse/util/jsonobject.py
index 6dce03dd3a..50516926f3 100644
--- a/synapse/util/jsonobject.py
+++ b/synapse/util/jsonobject.py
@@ -14,7 +14,7 @@
 # limitations under the License.
 
 
-class JsonEncodedObject(object):
+class JsonEncodedObject:
     """ A common base class for defining protocol units that are represented
     as JSON.
 
diff --git a/synapse/util/metrics.py b/synapse/util/metrics.py
index 13775b43f9..6e57c1ee72 100644
--- a/synapse/util/metrics.py
+++ b/synapse/util/metrics.py
@@ -93,7 +93,7 @@ def measure_func(name: Optional[str] = None) -> Callable[[T], T]:
     return wrapper
 
 
-class Measure(object):
+class Measure:
     __slots__ = [
         "clock",
         "name",
diff --git a/synapse/util/ratelimitutils.py b/synapse/util/ratelimitutils.py
index e5efdfcd02..70d11e1ec3 100644
--- a/synapse/util/ratelimitutils.py
+++ b/synapse/util/ratelimitutils.py
@@ -29,7 +29,7 @@ from synapse.logging.context import (
 logger = logging.getLogger(__name__)
 
 
-class FederationRateLimiter(object):
+class FederationRateLimiter:
     def __init__(self, clock, config):
         """
         Args:
@@ -60,7 +60,7 @@ class FederationRateLimiter(object):
         return self.ratelimiters[host].ratelimit()
 
 
-class _PerHostRatelimiter(object):
+class _PerHostRatelimiter:
     def __init__(self, clock, config):
         """
         Args:
diff --git a/synapse/util/retryutils.py b/synapse/util/retryutils.py
index 919988d3bc..79869aaa44 100644
--- a/synapse/util/retryutils.py
+++ b/synapse/util/retryutils.py
@@ -114,7 +114,7 @@ async def get_retry_limiter(destination, clock, store, ignore_backoff=False, **k
     )
 
 
-class RetryDestinationLimiter(object):
+class RetryDestinationLimiter:
     def __init__(
         self,
         destination,
diff --git a/synapse/util/wheel_timer.py b/synapse/util/wheel_timer.py
index 023beb5ede..be3b22469d 100644
--- a/synapse/util/wheel_timer.py
+++ b/synapse/util/wheel_timer.py
@@ -14,7 +14,7 @@
 # limitations under the License.
 
 
-class _Entry(object):
+class _Entry:
     __slots__ = ["end_key", "queue"]
 
     def __init__(self, end_key):
@@ -22,7 +22,7 @@ class _Entry(object):
         self.queue = []
 
 
-class WheelTimer(object):
+class WheelTimer:
     """Stores arbitrary objects that will be returned after their timers have
     expired.
     """
diff --git a/tests/api/test_auth.py b/tests/api/test_auth.py
index 5d45689c8c..8ab56ec94c 100644
--- a/tests/api/test_auth.py
+++ b/tests/api/test_auth.py
@@ -36,7 +36,7 @@ from tests import unittest
 from tests.utils import mock_getRawHeaders, setup_test_homeserver
 
 
-class TestHandlers(object):
+class TestHandlers:
     def __init__(self, hs):
         self.auth_handler = synapse.handlers.auth.AuthHandler(hs)
 
diff --git a/tests/crypto/test_keyring.py b/tests/crypto/test_keyring.py
index d264653e74..2e6e7abf1f 100644
--- a/tests/crypto/test_keyring.py
+++ b/tests/crypto/test_keyring.py
@@ -43,7 +43,7 @@ from tests import unittest
 from tests.test_utils import make_awaitable
 
 
-class MockPerspectiveServer(object):
+class MockPerspectiveServer:
     def __init__(self):
         self.server_name = "mock_server"
         self.key = signedjson.key.generate_signing_key(0)
diff --git a/tests/federation/transport/test_server.py b/tests/federation/transport/test_server.py
index 27d83bb7d9..72e22d655f 100644
--- a/tests/federation/transport/test_server.py
+++ b/tests/federation/transport/test_server.py
@@ -26,7 +26,7 @@ from tests.unittest import override_config
 
 class RoomDirectoryFederationTests(unittest.HomeserverTestCase):
     def prepare(self, reactor, clock, homeserver):
-        class Authenticator(object):
+        class Authenticator:
             def authenticate_request(self, request, content):
                 return defer.succeed("otherserver.nottld")
 
diff --git a/tests/handlers/test_auth.py b/tests/handlers/test_auth.py
index 4b3fb018b1..c7efd3822d 100644
--- a/tests/handlers/test_auth.py
+++ b/tests/handlers/test_auth.py
@@ -28,7 +28,7 @@ from tests.test_utils import make_awaitable
 from tests.utils import setup_test_homeserver
 
 
-class AuthHandlers(object):
+class AuthHandlers:
     def __init__(self, hs):
         self.auth_handler = AuthHandler(hs)
 
diff --git a/tests/handlers/test_profile.py b/tests/handlers/test_profile.py
index 60ebc95f3e..8e95e53d9e 100644
--- a/tests/handlers/test_profile.py
+++ b/tests/handlers/test_profile.py
@@ -28,7 +28,7 @@ from tests.test_utils import make_awaitable
 from tests.utils import setup_test_homeserver
 
 
-class ProfileHandlers(object):
+class ProfileHandlers:
     def __init__(self, hs):
         self.profile_handler = MasterProfileHandler(hs)
 
diff --git a/tests/http/__init__.py b/tests/http/__init__.py
index 2096ba3c91..5d41443293 100644
--- a/tests/http/__init__.py
+++ b/tests/http/__init__.py
@@ -133,7 +133,7 @@ def create_test_cert_file(sanlist):
 
 
 @implementer(IOpenSSLServerConnectionCreator)
-class TestServerTLSConnectionFactory(object):
+class TestServerTLSConnectionFactory:
     """An SSL connection creator which returns connections which present a certificate
     signed by our test CA."""
 
diff --git a/tests/http/federation/test_matrix_federation_agent.py b/tests/http/federation/test_matrix_federation_agent.py
index eb78ab412a..8b5ad4574f 100644
--- a/tests/http/federation/test_matrix_federation_agent.py
+++ b/tests/http/federation/test_matrix_federation_agent.py
@@ -1264,7 +1264,7 @@ def _log_request(request):
 
 
 @implementer(IPolicyForHTTPS)
-class TrustingTLSPolicyForHTTPS(object):
+class TrustingTLSPolicyForHTTPS:
     """An IPolicyForHTTPS which checks that the certificate belongs to the
     right server, but doesn't check the certificate chain."""
 
diff --git a/tests/logging/test_structured.py b/tests/logging/test_structured.py
index 451d05c0f0..d36f5f426c 100644
--- a/tests/logging/test_structured.py
+++ b/tests/logging/test_structured.py
@@ -29,12 +29,12 @@ from synapse.logging.context import LoggingContext
 from tests.unittest import DEBUG, HomeserverTestCase
 
 
-class FakeBeginner(object):
+class FakeBeginner:
     def beginLoggingTo(self, observers, **kwargs):
         self.observers = observers
 
 
-class StructuredLoggingTestBase(object):
+class StructuredLoggingTestBase:
     """
     Test base that registers a cleanup handler to reset the stdlib log handler
     to 'unset'.
diff --git a/tests/push/test_email.py b/tests/push/test_email.py
index 227b0d32d0..3224568640 100644
--- a/tests/push/test_email.py
+++ b/tests/push/test_email.py
@@ -27,7 +27,7 @@ from tests.unittest import HomeserverTestCase
 
 
 @attr.s
-class _User(object):
+class _User:
     "Helper wrapper for user ID and access token"
     id = attr.ib()
     token = attr.ib()
diff --git a/tests/rest/client/third_party_rules.py b/tests/rest/client/third_party_rules.py
index 7167fc56b6..8c24add530 100644
--- a/tests/rest/client/third_party_rules.py
+++ b/tests/rest/client/third_party_rules.py
@@ -19,7 +19,7 @@ from synapse.rest.client.v1 import login, room
 from tests import unittest
 
 
-class ThirdPartyRulesTestModule(object):
+class ThirdPartyRulesTestModule:
     def __init__(self, config):
         pass
 
diff --git a/tests/rest/client/v1/utils.py b/tests/rest/client/v1/utils.py
index e66c9a4c4c..afaf9f7b85 100644
--- a/tests/rest/client/v1/utils.py
+++ b/tests/rest/client/v1/utils.py
@@ -30,7 +30,7 @@ from tests.server import make_request, render
 
 
 @attr.s
-class RestHelper(object):
+class RestHelper:
     """Contains extra helper functions to quickly and clearly perform a given
     REST action, which isn't the focus of the test.
     """
diff --git a/tests/rest/media/v1/test_url_preview.py b/tests/rest/media/v1/test_url_preview.py
index 74765a582b..c00a7b9114 100644
--- a/tests/rest/media/v1/test_url_preview.py
+++ b/tests/rest/media/v1/test_url_preview.py
@@ -32,7 +32,7 @@ from tests.server import FakeTransport
 
 
 @attr.s
-class FakeResponse(object):
+class FakeResponse:
     version = attr.ib()
     code = attr.ib()
     phrase = attr.ib()
@@ -43,7 +43,7 @@ class FakeResponse(object):
     @property
     def request(self):
         @attr.s
-        class FakeTransport(object):
+        class FakeTransport:
             absoluteURI = self.absoluteURI
 
         return FakeTransport()
@@ -111,7 +111,7 @@ class URLPreviewTests(unittest.HomeserverTestCase):
 
         self.lookups = {}
 
-        class Resolver(object):
+        class Resolver:
             def resolveHostName(
                 _self,
                 resolutionReceiver,
diff --git a/tests/server.py b/tests/server.py
index b6e0b14e78..48e45c6c8b 100644
--- a/tests/server.py
+++ b/tests/server.py
@@ -35,7 +35,7 @@ class TimedOutException(Exception):
 
 
 @attr.s
-class FakeChannel(object):
+class FakeChannel:
     """
     A fake Twisted Web Channel (the part that interfaces with the
     wire).
@@ -242,7 +242,7 @@ class ThreadedMemoryReactorClock(MemoryReactorClock):
         lookups = self.lookups = {}
 
         @implementer(IResolverSimple)
-        class FakeResolver(object):
+        class FakeResolver:
             def getHostByName(self, name, timeout=None):
                 if name not in lookups:
                     return fail(DNSLookupError("OH NO: unknown %s" % (name,)))
@@ -371,7 +371,7 @@ def get_clock():
 
 
 @attr.s(cmp=False)
-class FakeTransport(object):
+class FakeTransport:
     """
     A twisted.internet.interfaces.ITransport implementation which sends all its data
     straight into an IProtocol object: it exists to connect two IProtocols together.
diff --git a/tests/state/test_v2.py b/tests/state/test_v2.py
index f2955a9c69..ad9bbef9d2 100644
--- a/tests/state/test_v2.py
+++ b/tests/state/test_v2.py
@@ -49,7 +49,7 @@ class FakeClock:
         return defer.succeed(None)
 
 
-class FakeEvent(object):
+class FakeEvent:
     """A fake event we use as a convenience.
 
     NOTE: Again as a convenience we use "node_ids" rather than event_ids to
@@ -595,7 +595,7 @@ def pairwise(iterable):
 
 
 @attr.s
-class TestStateResolutionStore(object):
+class TestStateResolutionStore:
     event_map = attr.ib()
 
     def get_events(self, event_ids, allow_rejected=False):
diff --git a/tests/storage/test__base.py b/tests/storage/test__base.py
index 319e2c2325..f5afed017c 100644
--- a/tests/storage/test__base.py
+++ b/tests/storage/test__base.py
@@ -99,7 +99,7 @@ class CacheTestCase(unittest.HomeserverTestCase):
 class CacheDecoratorTestCase(unittest.HomeserverTestCase):
     @defer.inlineCallbacks
     def test_passthrough(self):
-        class A(object):
+        class A:
             @cached()
             def func(self, key):
                 return key
@@ -113,7 +113,7 @@ class CacheDecoratorTestCase(unittest.HomeserverTestCase):
     def test_hit(self):
         callcount = [0]
 
-        class A(object):
+        class A:
             @cached()
             def func(self, key):
                 callcount[0] += 1
@@ -131,7 +131,7 @@ class CacheDecoratorTestCase(unittest.HomeserverTestCase):
     def test_invalidate(self):
         callcount = [0]
 
-        class A(object):
+        class A:
             @cached()
             def func(self, key):
                 callcount[0] += 1
@@ -149,7 +149,7 @@ class CacheDecoratorTestCase(unittest.HomeserverTestCase):
         self.assertEquals(callcount[0], 2)
 
     def test_invalidate_missing(self):
-        class A(object):
+        class A:
             @cached()
             def func(self, key):
                 return key
@@ -160,7 +160,7 @@ class CacheDecoratorTestCase(unittest.HomeserverTestCase):
     def test_max_entries(self):
         callcount = [0]
 
-        class A(object):
+        class A:
             @cached(max_entries=10)
             def func(self, key):
                 callcount[0] += 1
@@ -187,7 +187,7 @@ class CacheDecoratorTestCase(unittest.HomeserverTestCase):
 
         d = defer.succeed(123)
 
-        class A(object):
+        class A:
             @cached()
             def func(self, key):
                 callcount[0] += 1
@@ -205,7 +205,7 @@ class CacheDecoratorTestCase(unittest.HomeserverTestCase):
         callcount = [0]
         callcount2 = [0]
 
-        class A(object):
+        class A:
             @cached()
             def func(self, key):
                 callcount[0] += 1
@@ -238,7 +238,7 @@ class CacheDecoratorTestCase(unittest.HomeserverTestCase):
         callcount = [0]
         callcount2 = [0]
 
-        class A(object):
+        class A:
             @cached(max_entries=2)
             def func(self, key):
                 callcount[0] += 1
@@ -275,7 +275,7 @@ class CacheDecoratorTestCase(unittest.HomeserverTestCase):
         callcount = [0]
         callcount2 = [0]
 
-        class A(object):
+        class A:
             @cached()
             def func(self, key):
                 callcount[0] += 1
diff --git a/tests/test_state.py b/tests/test_state.py
index 56ba0fecf5..2d58467932 100644
--- a/tests/test_state.py
+++ b/tests/test_state.py
@@ -71,7 +71,7 @@ def create_event(
     return event
 
 
-class StateGroupStore(object):
+class StateGroupStore:
     def __init__(self):
         self._event_to_state_group = {}
         self._group_to_state = {}
@@ -129,7 +129,7 @@ class DictObj(dict):
         self.__dict__ = self
 
 
-class Graph(object):
+class Graph:
     def __init__(self, nodes, edges):
         events = {}
         clobbered = set(events.keys())
diff --git a/tests/test_visibility.py b/tests/test_visibility.py
index 4a4483ba12..510b630114 100644
--- a/tests/test_visibility.py
+++ b/tests/test_visibility.py
@@ -294,7 +294,7 @@ class FilterEventsForServerTestCase(tests.unittest.TestCase):
     test_large_room.skip = "Disabled by default because it's slow"
 
 
-class _TestStore(object):
+class _TestStore:
     """Implements a few methods of the DataStore, so that we can test
     filter_events_for_server
 
diff --git a/tests/unittest.py b/tests/unittest.py
index 7b80999a74..3cb55a7e96 100644
--- a/tests/unittest.py
+++ b/tests/unittest.py
@@ -614,7 +614,7 @@ class FederatingHomeserverTestCase(HomeserverTestCase):
     """
 
     def prepare(self, reactor, clock, homeserver):
-        class Authenticator(object):
+        class Authenticator:
             def authenticate_request(self, request, content):
                 return succeed("other.example.com")
 
diff --git a/tests/util/caches/test_descriptors.py b/tests/util/caches/test_descriptors.py
index 0363735d4f..677e925477 100644
--- a/tests/util/caches/test_descriptors.py
+++ b/tests/util/caches/test_descriptors.py
@@ -88,7 +88,7 @@ class CacheTestCase(unittest.TestCase):
 class DescriptorTestCase(unittest.TestCase):
     @defer.inlineCallbacks
     def test_cache(self):
-        class Cls(object):
+        class Cls:
             def __init__(self):
                 self.mock = mock.Mock()
 
@@ -122,7 +122,7 @@ class DescriptorTestCase(unittest.TestCase):
     def test_cache_num_args(self):
         """Only the first num_args arguments should matter to the cache"""
 
-        class Cls(object):
+        class Cls:
             def __init__(self):
                 self.mock = mock.Mock()
 
@@ -156,7 +156,7 @@ class DescriptorTestCase(unittest.TestCase):
         """If the wrapped function throws synchronously, things should continue to work
         """
 
-        class Cls(object):
+        class Cls:
             @cached()
             def fn(self, arg1):
                 raise SynapseError(100, "mai spoon iz too big!!1")
@@ -180,7 +180,7 @@ class DescriptorTestCase(unittest.TestCase):
 
         complete_lookup = defer.Deferred()
 
-        class Cls(object):
+        class Cls:
             @descriptors.cached()
             def fn(self, arg1):
                 @defer.inlineCallbacks
@@ -223,7 +223,7 @@ class DescriptorTestCase(unittest.TestCase):
         """Check that the cache sets and restores logcontexts correctly when
         the lookup function throws an exception"""
 
-        class Cls(object):
+        class Cls:
             @descriptors.cached()
             def fn(self, arg1):
                 @defer.inlineCallbacks
@@ -263,7 +263,7 @@ class DescriptorTestCase(unittest.TestCase):
 
     @defer.inlineCallbacks
     def test_cache_default_args(self):
-        class Cls(object):
+        class Cls:
             def __init__(self):
                 self.mock = mock.Mock()
 
@@ -300,7 +300,7 @@ class DescriptorTestCase(unittest.TestCase):
         obj.mock.assert_not_called()
 
     def test_cache_iterable(self):
-        class Cls(object):
+        class Cls:
             def __init__(self):
                 self.mock = mock.Mock()
 
@@ -336,7 +336,7 @@ class DescriptorTestCase(unittest.TestCase):
         """If the wrapped function throws synchronously, things should continue to work
         """
 
-        class Cls(object):
+        class Cls:
             @descriptors.cached(iterable=True)
             def fn(self, arg1):
                 raise SynapseError(100, "mai spoon iz too big!!1")
@@ -358,7 +358,7 @@ class DescriptorTestCase(unittest.TestCase):
 class CachedListDescriptorTestCase(unittest.TestCase):
     @defer.inlineCallbacks
     def test_cache(self):
-        class Cls(object):
+        class Cls:
             def __init__(self):
                 self.mock = mock.Mock()
 
@@ -408,7 +408,7 @@ class CachedListDescriptorTestCase(unittest.TestCase):
     def test_invalidate(self):
         """Make sure that invalidation callbacks are called."""
 
-        class Cls(object):
+        class Cls:
             def __init__(self):
                 self.mock = mock.Mock()
 
diff --git a/tests/util/test_file_consumer.py b/tests/util/test_file_consumer.py
index 8d6627ec33..2012263184 100644
--- a/tests/util/test_file_consumer.py
+++ b/tests/util/test_file_consumer.py
@@ -112,7 +112,7 @@ class FileConsumerTests(unittest.TestCase):
         self.assertTrue(string_file.closed)
 
 
-class DummyPullProducer(object):
+class DummyPullProducer:
     def __init__(self):
         self.consumer = None
         self.deferred = defer.Deferred()
@@ -134,7 +134,7 @@ class DummyPullProducer(object):
         return d
 
 
-class BlockingStringWrite(object):
+class BlockingStringWrite:
     def __init__(self):
         self.buffer = ""
         self.closed = False
diff --git a/tests/utils.py b/tests/utils.py
index a61cbdef44..4673872f88 100644
--- a/tests/utils.py
+++ b/tests/utils.py
@@ -472,7 +472,7 @@ class MockHttpResource(HttpServer):
             self.callbacks.append((method, path_pattern, callback))
 
 
-class MockKey(object):
+class MockKey:
     alg = "mock_alg"
     version = "mock_version"
     signature = b"\x9a\x87$"
@@ -491,7 +491,7 @@ class MockKey(object):
         return b"<fake_encoded_key>"
 
 
-class MockClock(object):
+class MockClock:
     now = 1000
 
     def __init__(self):
@@ -568,7 +568,7 @@ def _format_call(args, kwargs):
     )
 
 
-class DeferredMockCallable(object):
+class DeferredMockCallable:
     """A callable instance that stores a set of pending call expectations and
     return values for them. It allows a unit test to assert that the given set
     of function calls are eventually made, by awaiting on them to be called.