code: public LocalDate minusMonths(int months) {
          if (months == 0) {
              return this;
          }
          long instant = getChronology().months().subtract(getLocalMillis(), months);
          return withLocalMillis(instant);
      }
docs: Returns a copy of this date minus the specified number of months.
  <p>
  This subtracts the specified number of months from the date.
  The subtraction may change the year, but the day-of-month is normally unchanged.
  If subtracting months makes the day-of-month invalid, it is adjusted to the last valid day in the month.
  This LocalDate instance is immutable and unaffected by this method call.
  <p>
  The following three lines are identical in effect:
  <pre>
  LocalDate subtracted = dt.minusMonths(6);
  LocalDate subtracted = dt.minus(Period.months(6));
  LocalDate subtracted = dt.withFieldAdded(DurationFieldType.months(), -6);
  </pre>
  
  @param months  the amount of months to subtract, may be negative
  @return the new LocalDate minus the increased months