code: def _ParseDocstringArgSpec(doc):
      """Get an ArgSpec string from a method docstring.
  
      This method is used to generate argspec for C extension functions that follow
      pybind11 DocString format function signature. For example:
      `foo_function(a: int, b: string) -> None...`
  
      Args:
        doc: A python string which starts with function signature.
  
      Returns:
        string: a argspec string representation if successful. If not, return None.
  
      Raises:
        ValueError: Raised when failed to parse the input docstring.
      """
      # Check if the docstring begins with a function signature
      match = re.search(r"^\w+\(.*\)", doc)
      args_spec = _GenerateArgsSpec(doc)
      if (not match) or (args_spec is None):
          raise ValueError(
              f"Failed to parse argspec from docstring: {doc}"
          )
  
      # TODO(panzf): implement parsing docs with varargs, keywords, and defaults
      output_string = f"args=[{args_spec}], varargs=None, keywords=None, defaults=None"
      return output_string
  
file_path: tensorflow/tensorflow/tools/api/lib/python_object_to_proto_visitor.py
imports: import enum
  import re
  import sys
  from google.protobuf import message
  from tensorflow.python.platform import tf_logging
  from tensorflow.python.util import deprecation
  from tensorflow.python.util import tf_decorator
  from tensorflow.python.util import tf_inspect
  from tensorflow.tools.api.lib import api_objects_pb2
label_desc: Use image node_id 5 for calling a global function with example usage: _ParseDocstringArgSpec(doc) and returns: output_string