1 files changed, 28 insertions, 21 deletions

diff --git a/synapse/groups/attestations.py b/synapse/groups/attestations.py
index 41cf07cc88..a3f8d92d08 100644
--- a/synapse/groups/attestations.py
+++ b/synapse/groups/attestations.py
@@ -37,13 +37,16 @@ An attestation is a signed blob of json that looks like:
 
 import logging
 import random
-from typing import Tuple
+from typing import TYPE_CHECKING, Optional, Tuple
 
 from signedjson.sign import sign_json
 
 from synapse.api.errors import HttpResponseException, RequestSendFailed, SynapseError
 from synapse.metrics.background_process_metrics import run_as_background_process
-from synapse.types import get_domain_from_id
+from synapse.types import JsonDict, get_domain_from_id
+
+if TYPE_CHECKING:
+    from synapse.app.homeserver import HomeServer
 
 logger = logging.getLogger(__name__)
 
@@ -61,18 +64,21 @@ UPDATE_ATTESTATION_TIME_MS = 1 * 24 * 60 * 60 * 1000
 
 
 class GroupAttestationSigning:
-    """Creates and verifies group attestations.
-    """
+    """Creates and verifies group attestations."""
 
-    def __init__(self, hs):
+    def __init__(self, hs: "HomeServer"):
         self.keyring = hs.get_keyring()
         self.clock = hs.get_clock()
         self.server_name = hs.hostname
         self.signing_key = hs.signing_key
 
     async def verify_attestation(
-        self, attestation, group_id, user_id, server_name=None
-    ):
+        self,
+        attestation: JsonDict,
+        group_id: str,
+        user_id: str,
+        server_name: Optional[str] = None,
+    ) -> None:
         """Verifies that the given attestation matches the given parameters.
 
         An optional server_name can be supplied to explicitly set which server's
@@ -101,16 +107,18 @@ class GroupAttestationSigning:
         if valid_until_ms < now:
             raise SynapseError(400, "Attestation expired")
 
+        assert server_name is not None
         await self.keyring.verify_json_for_server(
             server_name, attestation, now, "Group attestation"
         )
 
-    def create_attestation(self, group_id, user_id):
+    def create_attestation(self, group_id: str, user_id: str) -> JsonDict:
         """Create an attestation for the group_id and user_id with default
         validity length.
         """
-        validity_period = DEFAULT_ATTESTATION_LENGTH_MS
-        validity_period *= random.uniform(*DEFAULT_ATTESTATION_JITTER)
+        validity_period = DEFAULT_ATTESTATION_LENGTH_MS * random.uniform(
+            *DEFAULT_ATTESTATION_JITTER
+        )
         valid_until_ms = int(self.clock.time_msec() + validity_period)
 
         return sign_json(
@@ -125,10 +133,9 @@ class GroupAttestationSigning:
 
 
 class GroupAttestionRenewer:
-    """Responsible for sending and receiving attestation updates.
-    """
+    """Responsible for sending and receiving attestation updates."""
 
-    def __init__(self, hs):
+    def __init__(self, hs: "HomeServer"):
         self.clock = hs.get_clock()
         self.store = hs.get_datastore()
         self.assestations = hs.get_groups_attestation_signing()
@@ -141,9 +148,10 @@ class GroupAttestionRenewer:
                 self._start_renew_attestations, 30 * 60 * 1000
             )
 
-    async def on_renew_attestation(self, group_id, user_id, content):
-        """When a remote updates an attestation
-        """
+    async def on_renew_attestation(
+        self, group_id: str, user_id: str, content: JsonDict
+    ) -> JsonDict:
+        """When a remote updates an attestation"""
         attestation = content["attestation"]
 
         if not self.is_mine_id(group_id) and not self.is_mine_id(user_id):
@@ -157,12 +165,11 @@ class GroupAttestionRenewer:
 
         return {}
 
-    def _start_renew_attestations(self):
+    def _start_renew_attestations(self) -> None:
         return run_as_background_process("renew_attestations", self._renew_attestations)
 
-    async def _renew_attestations(self):
-        """Called periodically to check if we need to update any of our attestations
-        """
+    async def _renew_attestations(self) -> None:
+        """Called periodically to check if we need to update any of our attestations"""
 
         now = self.clock.time_msec()
 
@@ -170,7 +177,7 @@ class GroupAttestionRenewer:
             now + UPDATE_ATTESTATION_TIME_MS
         )
 
-        async def _renew_attestation(group_user: Tuple[str, str]):
+        async def _renew_attestation(group_user: Tuple[str, str]) -> None:
             group_id, user_id = group_user
             try:
                 if not self.is_mine_id(group_id):