code: @Override
      public Temporal subtractFrom(Temporal temporal) {
          Jdk8Methods.requireNonNull(temporal, "temporal");
          if (years != 0) {
              if (months != 0) {
                  temporal = temporal.minus(toTotalMonths(), MONTHS);
              } else {
                  temporal = temporal.minus(years, YEARS);
              }
          } else if (months != 0) {
              temporal = temporal.minus(months, MONTHS);
          }
          if (days != 0) {
              temporal = temporal.minus(days, DAYS);
          }
          return temporal;
      }
docs: Subtracts this period from the specified temporal object.
  <p>
  This returns a temporal object of the same observable type as the input
  with this period subtracted.
  <p>
  In most cases, it is clearer to reverse the calling pattern by using
  {@link Temporal#minus(TemporalAmount)}.
  <pre>
  // these two lines are equivalent, but the second approach is recommended
  dateTime = thisPeriod.subtractFrom(dateTime);
  dateTime = dateTime.minus(thisPeriod);
  </pre>
  <p>
  The calculation operates as follows.
  First, the chronology of the temporal is checked to ensure it is ISO chronology or null.
  Second, if the months are zero, the years are added if non-zero, otherwise
  the combination of years and months is added if non-zero.
  Finally, any days are added.
  
  The calculation will subtract the years, then months, then days.
  Only non-zero amounts will be subtracted.
  If the date-time has a calendar system with a fixed number of months in a
  year, then the years and months will be combined before being subtracted.
  <p>
  This instance is immutable and unaffected by this method call.
  
  @param temporal  the temporal object to adjust, not null
  @return an object of the same type with the adjustment made, not null
  @throws DateTimeException if unable to subtract
  @throws ArithmeticException if numeric overflow occurs