(#159) when we exhaust the only remaining bucket, we should return No…

…ne so that the epoch completes

helpers/multiaspect/sampler.py

@@ -399,6 +399,7 @@ def __iter__(self):
                         f"Our only bucket {self.current_bucket} is exhausted, so we reset."
                     )
                     self._reset_buckets()
+                    return
 
             if all_buckets_exhausted:
                 # If all buckets are exhausted, reset the seen images and refresh buckets