code: def bridge_param(_param, _method, *args, **kwargs):
      
      assert callable(_method), "method %r is not callable" % (_method, )
      f = Fiber(debug_depth=1, debug_call=_method)
      f.add_callback(drop_param, _method, *args, **kwargs)
      f.add_callback(override_result, _param)
      return f.succeed()
docs: Used as a callback to keep the result from the previous callback
      and use that instead of the result of the given callback when
      chaining to the next callback in the fiber.