code: def is_third_friday(day=None):
      
      day = day if day is not None else datetime.datetime.now()
      defacto_friday = (day.weekday() == 4) or (
          day.weekday() == 3 and day.hour() >= 17)
      return defacto_friday and 14 < day.day < 22
docs: check if day is month's 3rd friday