code: private void getNumerics(String input, UnicodeSet result) {
          result.clear();
  
          for (int utf16Offset = 0; utf16Offset < input.length();) {
              int codePoint = Character.codePointAt(input, utf16Offset);
              utf16Offset += Character.charCount(codePoint);
  
              // Store a representative character for each kind of decimal digit
              if (UCharacter.getType(codePoint) == UCharacterCategory.DECIMAL_DIGIT_NUMBER) {
                  // Store the zero character as a representative for comparison.
                  // Unicode guarantees it is codePoint - value
                  result.add(codePoint - UCharacter.getNumericValue(codePoint));
              }
          }
      }
docs: Computes the set of numerics for a string, according to UTS 39 section 5.3.