message: Add tf.contrib.checkpoint.list_objects for listing all Python dependencies of a
  checkpointable object
  Useful for asserting that all expected objects have been added as dependencies
  in a unit test.
diff: Visualization and inspection:
  @@dot_graph_from_checkpoint
  +@@list_objects
  @@object_metadata
  Managing dependencies:
  @@ -42,9 +43,9 @@ from tensorflow.python.training.checkpointable.base import Checkpointable
  from tensorflow.python.training.checkpointable.base import NoDependency
  from tensorflow.python.training.checkpointable.data_structures import List
  from tensorflow.python.training.checkpointable.data_structures import Mapping
  +from tensorflow.python.training.checkpointable.util import list_objects
  from tensorflow.python.training.checkpointable.util import object_metadata
  from tensorflow.python.util.all_util import remove_undocumented
  remove_undocumented(module_name=__name__)
  -
  