code: def GetStartTime(self, problems=problems_module.default_problem_reporter):
      
      cursor = self._schedule._connection.cursor()
      cursor.execute(
          'SELECT arrival_secs,departure_secs FROM stop_times WHERE '
          'trip_id=? ORDER BY stop_sequence LIMIT 1', (self.trip_id,))
      (arrival_secs, departure_secs) = cursor.fetchone()
      if arrival_secs != None:
        return arrival_secs
      elif departure_secs != None:
        return departure_secs
      else:
        problems.InvalidValue('departure_time', '',
                              'The first stop_time in trip %s is missing '
                              'times.' % self.trip_id)
docs: Return the first time of the trip. TODO: For trips defined by frequency
      return the first time of the first trip.