code: def _tf_core_flatten(structure, expand_composites=False):
      """See comments for flatten() in tensorflow/python/util/nest.py."""
      if structure is None:
          return [None]
      expand_composites = bool(expand_composites)
      return _pywrap_utils.Flatten(structure, expand_composites)
  
imports: import collections
  import enum
  import wrapt
  from tensorflow.python import pywrap_tensorflow
  from tensorflow.python.platform import tf_logging
  from tensorflow.python.util import _pywrap_utils
  from tensorflow.python.util.compat import collections_abc
  from tensorflow.python.util.custom_nest_protocol import CustomNestProtocol
label_desc: Use image node_id 18 for calling a global function with example usage: _tf_core_flatten(structure, expand_composites) and returns: _pywrap_utils, list