code: def _ProcessReturnElementsParam(return_elements):
      """Type-checks and possibly canonicalizes `return_elements`."""
      if return_elements is None:
          return None
      if not all(
          isinstance(x, compat.bytes_or_text_types)
          for x in return_elements
      ):
          raise TypeError(
              "Argument `return_elements` must be a list of strings. "
              f"Obtained {return_elements}."
          )
      return tuple(compat.as_str(x) for x in return_elements)
  
imports: import contextlib
  from tensorflow.core.framework import graph_pb2
  from tensorflow.python import tf2
  from tensorflow.python.client import pywrap_tf_session
  from tensorflow.python.framework import c_api_util
  from tensorflow.python.framework import device
  from tensorflow.python.framework import errors
  from tensorflow.python.framework import function
  from tensorflow.python.framework import op_def_registry
  from tensorflow.python.framework import ops
  from tensorflow.python.framework import tensor
  from tensorflow.python.ops import control_flow_util
  from tensorflow.python.util import compat
  from tensorflow.python.util.deprecation import deprecated_args
  from tensorflow.python.util.tf_export import tf_export
label_desc: Use image node_id 6 for calling a global function with example usage: _ProcessReturnElementsParam(return_elements) and returns: tuple, None