# A
def _create_months_interval(start, end):
    while True:
        yield (start, start + relativedelta(day=31))

        start = start + relativedelta(months=1)
        if start > end:
            break

# B
def _create_months_interval(start, end):
    dates = list(rrule(MONTHLY, bymonthday=(1,-1), dtstart=start, until=end)
    return [dates[i:i+2] for i in range(0, len(dates), 2)]