code: def generate_skeleton_backward_function_impl(
      function_info, template, output_dir, output_format="%s.py"
  ):
      """This function now generate the template of a backward function in python-layer using PythonFunction."""
      from mako.template import Template
      import os
  
      for name, func in function_info.items():
          path_o = join(output_dir, output_format % func["snake_name"])
          if os.path.exists(path_o):
              continue
          # Create the skelton file of the backward function
          generated = render_with_template(
              filename=template, template_kwargs=dict(func=func)
          )
          check_update(path_o, generated, force=False)
  
imports: from __future__ import print_function
  from collections import OrderedDict
  from os.path import abspath, join, dirname, exists
  from utils.common import check_update
  from utils.type_conv import type_from_proto
  import time
  import yaml
label_desc: Use image node_id 21 for calling a global function with example usage: generate_skeleton_backward_function_impl(function_info, template, output_dir, output_format) without return types