docs: def _parse_ical_string(ical_string):
      """
      SU,MO,TU,WE,TH,FR,SA
      DTSTART;TZID=America/New_York:20180804T233251\nRRULE:FREQ=WEEKLY;BYDAY=SA
      DTSTART;TZID=America/New_York:20180804T233251\nRRULE:FREQ=DAILY
      DTSTART;TZID=America/New_York:20180804T233251\nRRULE:FREQ=WEEKLY;BYDAY=MO,TU,WE,TH,FR,SA
      DTSTART;TZID=America/New_York:20180718T174500
      """
      start_time = ical_string.splitlines()[0].replace(DTSTART, '')
      if "RRULE" in ical_string:
          days = ical_string.splitlines()[1].replace(REPEAT, '')
          if days == "RRULE:FREQ=DAILY":
              days = ['DAILY']
          else:
              days = days.split(',')
      else:
          days = None
      start_time = start_time.splitlines()[0].split(':')[1]
      datetime_object = datetime.strptime(start_time, '%Y%m%dT%H%M%S')
      return datetime_object, days