docs: def merge_response_func(func, key):
      """
          Use this decorator to set a new merging
          response function to HTTP endpoints
  
          candidate function must have the following signature
          and be childs of BaseApi:
          ```
              def merge_some_function(self, response, rison_args):
          ```
  
      :param func: Name of the merge function where the key is allowed
      :param key: The key name for rison selection
      :return: None
      """
  
      def wrap(f):
          if not hasattr(f, "_response_key_func_mappings"):
              f._response_key_func_mappings = dict()
          f._response_key_func_mappings[key] = func
          return f
  
      return wrap