code: def _add_op_to_signature_def_map(signature_def_map, op, key):
      if op is not None:
          signature_def_map[key] = signature_def_utils.op_signature_def(
              op, key
          )
  
imports: import functools
  import os
  from google.protobuf.any_pb2 import Any
  from tensorflow.core.framework import types_pb2
  from tensorflow.core.protobuf import meta_graph_pb2
  from tensorflow.core.protobuf import saved_model_pb2
  from tensorflow.core.protobuf import saver_pb2
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import ops
  from tensorflow.python.framework import tensor
  from tensorflow.python.lib.io import file_io
  from tensorflow.python.ops import variables
  from tensorflow.python.platform import tf_logging
  from tensorflow.python.saved_model import fingerprinting_utils
  from tensorflow.python.saved_model import path_helpers
  from tensorflow.python.saved_model import signature_def_utils
  from tensorflow.python.saved_model.pywrap_saved_model import constants
  from tensorflow.python.saved_model.pywrap_saved_model import metrics
  from tensorflow.python.training import saver
  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 8 for calling a global function with example usage: _add_op_to_signature_def_map(signature_def_map, op, key) without return types