Checks if a range is included either in 0-9, a-z or A-Z
@param classRange
@returns {boolean}
function isSimpleRange(classRange) {
  const {from, to} = classRange;
  return (
    from.codePoint >= DIGIT_0_CP && from.codePoint <= DIGIT_9_CP &&
    to.codePoint >= DIGIT_0_CP && to.codePoint <= DIGIT_9_CP
  ) || (
    from.codePoint >= UPPER_A_CP && from.codePoint <= UPPER_Z_CP &&
    to.codePoint >= UPPER_A_CP && to.codePoint <= UPPER_Z_CP
  ) || (
    from.codePoint >= LOWER_A_CP && from.codePoint <= LOWER_Z_CP &&
    to.codePoint >= LOWER_A_CP && to.codePoint <= LOWER_Z_CP
  );
}