1 files changed, 12 insertions, 11 deletions
diff --git a/synapse/util/distributor.py b/synapse/util/distributor.py
index 1f803aef6d..31097d6439 100644
--- a/synapse/util/distributor.py
+++ b/synapse/util/distributor.py
@@ -12,6 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import logging
+from typing import Any, Callable, Dict, List
 
 from twisted.internet import defer
 
@@ -37,11 +38,11 @@ class Distributor:
       model will do for today.
     """
 
-    def __init__(self):
-        self.signals = {}
-        self.pre_registration = {}
+    def __init__(self) -> None:
+        self.signals: Dict[str, Signal] = {}
+        self.pre_registration: Dict[str, List[Callable]] = {}
 
-    def declare(self, name):
+    def declare(self, name: str) -> None:
         if name in self.signals:
             raise KeyError("%r already has a signal named %s" % (self, name))
 
@@ -52,7 +53,7 @@ class Distributor:
             for observer in self.pre_registration[name]:
                 signal.observe(observer)
 
-    def observe(self, name, observer):
+    def observe(self, name: str, observer: Callable) -> None:
         if name in self.signals:
             self.signals[name].observe(observer)
         else:
@@ -62,7 +63,7 @@ class Distributor:
                 self.pre_registration[name] = []
             self.pre_registration[name].append(observer)
 
-    def fire(self, name, *args, **kwargs):
+    def fire(self, name: str, *args, **kwargs) -> None:
         """Dispatches the given signal to the registered observers.
 
         Runs the observers as a background process. Does not return a deferred.
@@ -83,18 +84,18 @@ class Signal:
     method into all of the observers.
     """
 
-    def __init__(self, name):
-        self.name = name
-        self.observers = []
+    def __init__(self, name: str):
+        self.name: str = name
+        self.observers: List[Callable] = []
 
-    def observe(self, observer):
+    def observe(self, observer: Callable) -> None:
         """Adds a new callable to the observer list which will be invoked by
         the 'fire' method.
 
         Each observer callable may return a Deferred."""
         self.observers.append(observer)
 
-    def fire(self, *args, **kwargs):
+    def fire(self, *args, **kwargs) -> "defer.Deferred[List[Any]]":
         """Invokes every callable in the observer list, passing in the args and
         kwargs. Exceptions thrown by observers are logged but ignored. It is
         not an error to fire a signal with no observers.