docs: def _get_weekly_date_range(self, metric_date, delta):
          """
          Gets the range of years that we need to use as keys to get metrics from redis.
          """
          dates = [metric_date]
          end_date = metric_date + delta
          #Figure out how many years our metric range spans
          spanning_years = end_date.year - metric_date.year
          for i in range(spanning_years):
              #for the weekly keys, we only care about the year
              dates.append(
                  datetime.date(
                      year=metric_date.year + (i + 1), month=1, day=1))
          return dates