code: def next_event_description(self):
          
          if self._departures[0]._time < self._arrivals[0]._time:
              return 2
          elif self._arrivals[0]._time < infty:
              return 1
          else:
              return 0
docs: Returns an integer representing whether the next event is
          an arrival, a departure, or nothing.
  
          Returns
          -------
          out : int
              An integer representing whether the next event is an
              arrival or a departure: ``1`` corresponds to an arrival,
              ``2`` corresponds to a departure, and ``0`` corresponds to
              nothing scheduled to occur.