docs: def round_to_quarter(start_time, end_time):
      """
      Return the duration between `start_time` and `end_time` :class:`datetime.time` objects, rounded to 15 minutes.
      """
      # We don't care about the date (only about the time) but Python
      # can substract only datetime objects, not time ones
      today = datetime.date.today()
      start_date = datetime.datetime.combine(today, start_time)
      end_date = datetime.datetime.combine(today, end_time)
  
      difference_minutes = (end_date - start_date).seconds / 60
      remainder = difference_minutes % 15
      # Round up
      difference_minutes += 15 - remainder if remainder > 0 else 0
  
      return (
          start_date + datetime.timedelta(minutes=difference_minutes)
      ).time()