code: def _signature_str(function_name, arg_spec):
      """Helper function to output a function signature"""
      # inspect.formatargspec can not deal with the same
      # number of arguments in python 2 and 3
      arg_spec_for_format = arg_spec[: 7 if PY3_OR_LATER else 4]
  
      arg_spec_str = inspect.formatargspec(*arg_spec_for_format)
      return "{}{}".format(function_name, arg_spec_str)
  
file_path: mlens/mlens/externals/joblib/func_inspect.py
imports: from itertools import islice
  import inspect
  import warnings
  import re
  import os
  from ._compat import _basestring
  from .logger import pformat
  from ._memory_helpers import open_py_source
  from ._compat import PY3_OR_LATER
label_desc: Use image node_id 5 for calling a global function with example usage: _signature_str(function_name, arg_spec) and returns: str