docs: public MonetaryFormat digits(char zeroDigit) {
          if (zeroDigit == this.zeroDigit)
              return this;
          else
              return new MonetaryFormat(negativeSign, positiveSign, zeroDigit, decimalMark, minDecimals, decimalGroups,
                      shift, roundingMode, codes, codeSeparator, codePrefixed);
      }