* @return A {@link CopyOptions} with a number converter applied.
     * @see CopyOptions#numberConverter(String, CharSequence...)
     * @see NumberConverter
     */
    public static CopyOptions numberConverter(final String pattern, final CharSequence... propertyNames) {
        return new CopyOptions().numberConverter(pattern, propertyNames);
    }

     * @return This instance itself
     * @see NumberConverter
     */
    public CopyOptions numberConverter(final String pattern, final CharSequence... propertyNames) {
        assertArgumentNotEmpty("pattern", pattern);

        return converter(new NumberConverter(pattern), propertyNames);
    }

    /**