do_add_default_stream: Fix return value if stream exists.

timabbott · timabbott · commit fc02ea9f674e · 2016-02-03T19:28:48.000-08:00
Discovered using mypy static type checker.
diff --git a/zerver/lib/actions.py b/zerver/lib/actions.py
@@ -1878,7 +1878,7 @@ def set_default_streams(realm, stream_names):
 def do_add_default_stream(realm, stream_name):
     stream, _ = create_stream_if_needed(realm, stream_name)
     if DefaultStream.objects.filter(realm=realm, stream=stream).exists():
-        return
+        return {}
     DefaultStream.objects.create(realm=realm, stream=stream)
     return {}
 
