code: private int appendInternal(DateTimePrinterParser pp) {
          Jdk8Methods.requireNonNull(pp, "pp");
          if (active.padNextWidth > 0) {
              if (pp != null) {
                  pp = new PadPrinterParserDecorator(pp, active.padNextWidth, active.padNextChar);
              }
              active.padNextWidth = 0;
              active.padNextChar = 0;
          }
          active.printerParsers.add(pp);
          active.valueParserIndex = -1;
          return active.printerParsers.size() - 1;
      }
docs: Appends a printer and/or parser to the internal list handling padding.
  
  @param pp  the printer-parser to add, not null
  @return the index into the active parsers list