docs: def parse_schedule(schedule, action):
          """ parses the given schedule and validates at """
          error = None
          scheduled_at = None
          try:
              scheduled_at = dateutil.parser.parse(schedule)
              if scheduled_at.tzinfo is None:
                  error = 'Timezone information is mandatory for the scheduled {0}'.format(action)
                  status_code = 400
              elif scheduled_at < datetime.datetime.now(tzutc):
                  error = 'Cannot schedule {0} in the past'.format(action)
                  status_code = 422
              else:
                  status_code = None
          except (ValueError, TypeError):
              logger.exception('Invalid scheduled %s time: %s', action, schedule)
              error = 'Unable to parse scheduled timestamp. It should be in an unambiguous format, e.g. ISO 8601'
              status_code = 422
          return (status_code, error, scheduled_at)