def _index_of_day(self, day):
        year, isoweekday, weekday = day.isocalendar()
        return (isoweekday - 1) * 5 + weekday - 1
takes a VSeq of 3 notes and returns an HSeq of those notes in an
dataset/ETHPy150Open yinhm/datafeed/datafeed/datastore.py/Day._index_of_day--crossover with--dataset/ETHPy150Open jtauber/sebastian/experimental/alberti.py/alberti