code: def event_at(self, when, data_tuple):
          
          return self._base.event_at(when, self.make_event_data(*data_tuple))
docs: Schedule an event to be emitted at a certain time.
  
          :param when: an absolute timestamp
          :param data_tuple: a 2-tuple (flavor, data)
          :return: an event object, useful for cancelling.