docs: public static String number(int numberOfDigits) {
          if (numberOfDigits < 1) {
              return "";
          }
  
  
          StringBuffer sb = new StringBuffer(randomIntBetweenTwoNumbers(1, 9) + "");
  
          if (numberOfDigits == 1) {
              return sb.toString();
          }
  
  
          char[] chars = "123456789".toCharArray();
          String secondHalf = RandomStringUtils.random(numberOfDigits - 1, 0, 8, false, false, chars);
          return sb.append(secondHalf).toString();
      }