code: protected final LocalDate minusYearsAdjustToBegin(final LocalDate date,
              final int years) {
          final LocalDate adjustedYears = minusYears(date, years);
          final LocalDate firstMonth = firstMonth(adjustedYears);
          return firstDayOfMonth(firstMonth);
      }
docs: Subtract years from the date and then adjust to the beginning of the
  resultant year.
  
  @param date input date
  @param years years to add
  @return new date