code: public MoneyFormatterBuilder append(MoneyFormatter formatter) {
          MoneyFormatter.checkNotNull(formatter, "MoneyFormatter must not be null");
          formatter.getPrinterParser().appendTo(this);
          return this;
      }
docs: Appends the printers and parsers from the specified formatter to this builder.
  <p>
  If the specified formatter cannot print, then the the output of this
  builder will be unable to print. If the specified formatter cannot parse,
  then the output of this builder will be unable to parse.
  
  @param formatter  the formatter to append, not null
  @return this for chaining, never null