public MatchType isNumberMatch(PhoneNumber firstNumberIn, PhoneNumber secondNumberIn) {
// Make copies of the phone number so that the numbers passed in are not edited.
PhoneNumber firstNumber = new PhoneNumber();
firstNumber.mergeFrom(firstNumberIn);
PhoneNumber secondNumber = new PhoneNumber();
secondNumber.mergeFrom(secondNumberIn);
// First clear raw_input and country_code_source field and any empty-string extensions so that
// we can use the PhoneNumber.exactlySameAs() method.
firstNumber.clearRawInput();
firstNumber.clearCountryCodeSource();
secondNumber.clearRawInput();