message: Revoked removal of instance check
diff: @@ -971,7 +971,9 @@ class CheckpointLoadStatus(_LoadStatus):
  for checkpointable_object in list_objects(self._root_checkpointable):
  # Remove data structures that do not contain any variables from
  # restoration checks.
  - if not checkpointable_object._checkpoint_dependencies:
  + if (isinstance(checkpointable_object,
  + data_structures.CheckpointableDataStructure) and
  + not checkpointable_object._checkpoint_dependencies):
  continue
  self._checkpoint.all_python_objects.add(checkpointable_object)
  unused_python_objects = (
  