diff --git a/changelog.d/9649.misc b/changelog.d/9649.misc
new file mode 100644
index 0000000000..58c5fd0537
--- /dev/null
+++ b/changelog.d/9649.misc
@@ -0,0 +1 @@
+Fixed some antipattern issues to improve code quality.
diff --git a/scripts/move_remote_media_to_new_store.py b/scripts/move_remote_media_to_new_store.py
index ab2e763386..8477955a90 100755
--- a/scripts/move_remote_media_to_new_store.py
+++ b/scripts/move_remote_media_to_new_store.py
@@ -51,7 +51,7 @@ def main(src_repo, dest_repo):
         parts = line.split("|")
         if len(parts) != 2:
             print("Unable to parse input line %s" % line, file=sys.stderr)
-            exit(1)
+            sys.exit(1)
 
         move_media(parts[0], parts[1], src_paths, dest_paths)
 
diff --git a/synapse/push/httppusher.py b/synapse/push/httppusher.py
index eb6de8ba72..026134ae26 100644
--- a/synapse/push/httppusher.py
+++ b/synapse/push/httppusher.py
@@ -290,7 +290,7 @@ class HttpPusher(Pusher):
         if rejected is False:
             return False
 
-        if isinstance(rejected, list) or isinstance(rejected, tuple):
+        if isinstance(rejected, (list, tuple)):
             for pk in rejected:
                 if pk != self.pushkey:
                     # for sanity, we only remove the pushkey if it
diff --git a/synapse/util/frozenutils.py b/synapse/util/frozenutils.py
index 5f7a6dd1d3..5ca2e71e60 100644
--- a/synapse/util/frozenutils.py
+++ b/synapse/util/frozenutils.py
@@ -36,7 +36,7 @@ def freeze(o):
 
 def unfreeze(o):
     if isinstance(o, (dict, frozendict)):
-        return dict({k: unfreeze(v) for k, v in o.items()})
+        return {k: unfreeze(v) for k, v in o.items()}
 
     if isinstance(o, (bytes, str)):
         return o