code: def registered_identifiers():
      """Return all the current registered revived object identifiers.
  
      Returns:
        A set of strings.
      """
      return _REVIVED_TYPE_REGISTRY.keys()
  
file_path: tensorflow-upstream/tensorflow/python/saved_model/revived_types.py
imports: import operator
  from tensorflow.core.framework import versions_pb2
  from tensorflow.core.protobuf import saved_object_graph_pb2
  from tensorflow.python.trackable import data_structures
  from tensorflow.python.util.tf_export import tf_export
label_desc: Use image node_id 4 for calling a global function with example usage: registered_identifiers() and returns: _REVIVED_TYPE_REGISTRY