code: def get_callable_handler_function(src, handler):
      
  
      # "cd" into `src` directory.
      os.chdir(src)
  
      module_name, function_name = handler.split('.')
      filename = get_handler_filename(handler)
  
      path_to_module_file = os.path.join(src, filename)
      module = load_source(module_name, path_to_module_file)
      return getattr(module, function_name)
docs: Tranlate a string of the form "module.function" into a callable
      function.
  
      :param str src:
        The path to your Lambda project containing a valid handler file.
      :param str handler:
        A dot delimited string representing the `<module>.<function name>`.