Add type hints to the push module. (#8901)

scripts-dev/mypy_synapse_plugin.py

@@ -31,6 +31,8 @@ class SynapsePlugin(Plugin):
     ) -> Optional[Callable[[MethodSigContext], CallableType]]:
         if fullname.startswith(
             "synapse.util.caches.descriptors._CachedFunction.__call__"
+        ) or fullname.startswith(
+            "synapse.util.caches.descriptors._LruCachedFunction.__call__"
         ):
             return cached_function_method_signature
         return None