check for None

hivemind/averaging/averager.py

@@ -455,9 +455,10 @@ class DecentralizedAverager(mp.Process, ServicerBase):
 
                     group_info = await matchmaking_task
 
+                    if group_info is None:
+                        raise AllreduceException("Averaging step failed: could not find a group")
+
                     with self._register_allreduce_group(group_info):
-                        if group_info is None:
-                            raise AllreduceException("Averaging step failed: could not find a group")
 
                         step.stage = AveragingStage.RUNNING_ALLREDUCE