When people enter their telephone numbers into a form they use many different formats. Some examples are:

   (444) 999-1234
   4449991234
   444.999.1234
In the PhoneNumbers class below, complete the cleanNumber method. It takes a string and extracts the numeric digits from the string. If there are exactly 10 numeric digits, the number is reformatted: (###) ###-#### and returned. If there are any other number of digits, the string "Error" is returned.

Hint: Use the Character.isDigit method to check whether a character is a digit.

Complete the following file:

PhoneNumbers.java

public class PhoneNumbers { /** Cleans a phone number. @param phoneNumber a phone number that should contain ten digits and possibly other characters @return the phone number in the form (###) ###-#### or the string "Error" if phoneNumber does not have ten digits */ public String cleanNumber(String phoneNumber) { // your work here ... for (int i = 0; i < ...; i++) { char ch = phoneNumber.charAt(i); if (Character.isDigit(ch)) { ... } } ... } }