fix up some key verif docstrings

synapse/crypto/keyring.py

@@ -238,8 +238,14 @@ class Keyring(object):
             d.addBoth(rm, server_name)
 
     def get_server_verify_keys(self, verify_requests):
-        """Takes a dict of KeyGroups and tries to find at least one key for
-        each group.
+        """Tries to find at least one key for each verify request
+
+        For each verify_request, verify_request.deferred is called back with
+        params (server_name, key_id, VerifyKey) if a key is found, or errbacked
+        with a SynapseError if none of the keys are found.
+
+        Args:
+            verify_requests (list[VerifyKeyRequest]): list of verify requests
         """
 
         # These are functions that produce keys given a list of key ids
@@ -252,8 +258,11 @@ class Keyring(object):
         @defer.inlineCallbacks
         def do_iterations():
             with Measure(self.clock, "get_server_verify_keys"):
+                # dict[str, dict[str, VerifyKey]]: results so far.
+                # map server_name -> key_id -> VerifyKey
                 merged_results = {}
 
+                # dict[str, set(str)]: keys to fetch for each server
                 missing_keys = {}
                 for verify_request in verify_requests:
                     missing_keys.setdefault(verify_request.server_name, set()).update(
@@ -315,6 +324,16 @@ class Keyring(object):
 
     @defer.inlineCallbacks
     def get_keys_from_store(self, server_name_and_key_ids):
+        """
+
+        Args:
+            server_name_and_key_ids (list[(str, iterable[str])]):
+                list of (server_name, iterable[key_id]) tuples to fetch keys for
+
+        Returns:
+            Deferred: resolves to dict[str, dict[str, VerifyKey]]: map from
+                server_name -> key_id -> VerifyKey
+        """
         res = yield preserve_context_over_deferred(defer.gatherResults(
             [
                 preserve_fn(self.store.get_server_verify_keys)(

synapse/storage/keys.py

@@ -101,9 +101,10 @@ class KeyStore(SQLBaseStore):
         key_ids
         Args:
             server_name (str): The name of the server.
-            key_ids (list of str): List of key_ids to try and look up.
+            key_ids (iterable[str]): key_ids to try and look up.
         Returns:
-            (list of VerifyKey): The verification keys.
+            Deferred: resolves to dict[str, VerifyKey]: map from
+               key_id to verification key.
         """
         keys = {}
         for key_id in key_ids: