code: def put_event(self, evt):
          
          evt.step = self.global_step
          evt.wall_time = time.time()
          self._dispatch(lambda m: m.process_event(evt))
docs: Put an :class:`tf.Event`.
          `step` and `wall_time` fields of :class:`tf.Event` will be filled automatically.
  
          Args:
              evt (tf.Event):