code: def callback(self, position):
          
  
          callbacks = self.stage_config.get('callbacks', {})
          callback = callbacks.get(position)
  
          if callback:
              (mod_path, cb_func_name) = callback.rsplit('.', 1)
  
              try:  # Prefer callback in working directory
                  if mod_path.count('.') >= 1:  # Callback function is nested in a folder
                      (mod_folder_path, mod_name) = mod_path.rsplit('.', 1)
                      mod_folder_path_fragments = mod_folder_path.split('.')
                      working_dir = os.path.join(os.getcwd(), *mod_folder_path_fragments)
                  else:
                      mod_name = mod_path
                      working_dir = os.getcwd()
  
                  working_dir_importer = pkgutil.get_importer(working_dir)
                  module_ = working_dir_importer.find_module(mod_name).load_module(mod_name)
  
              except (ImportError, AttributeError):
  
                  try: # Callback func might be in virtualenv
                      module_ = importlib.import_module(mod_path)
                  except ImportError: # pragma: no cover
                      raise ClickException(click.style("Failed ", fg="red") + 'to ' + click.style(
                          "import {position} callback ".format(position=position),
                          bold=True) + 'module: "{mod_path}"'.format(mod_path=click.style(mod_path, bold=True)))
  
              if not hasattr(module_, cb_func_name): # pragma: no cover
                  raise ClickException(click.style("Failed ", fg="red") + 'to ' + click.style(
                      "find {position} callback ".format(position=position), bold=True) + 'function: "{cb_func_name}" '.format(
                      cb_func_name=click.style(cb_func_name, bold=True)) + 'in module "{mod_path}"'.format(mod_path=mod_path))
  
  
              cb_func = getattr(module_, cb_func_name)
              cb_func(self)
docs: Allows the execution of custom code between creation of the zip file and deployment to AWS.
  
          :return: None