code: public static Optional<BigDecimal> createBigDecimal(final String str) {
          if (N.isNullOrEmptyOrBlank(str) || str.trim().startsWith("--")) {
              return Optional.empty();
          }
  
          try {
              return Optional.of(new BigDecimal(str));
          } catch (NumberFormatException e) {
              return Optional.empty();
          }
      }
docs: <p>
  Convert a <code>String</code> to a <code>BigDecimal</code>.
  </p>
  
  <p>
  Returns an empty {@code Optional} if the string is {@code null} or can't be parsed as {@code BigDecimal}.
  </p>
  
  @param str a <code>String</code> to convert, may be null
  @return