code: func IsNumberMatch(firstNumber, secondNumber string) MatchType {
  	firstNumberAsProto, err := Parse(firstNumber, UNKNOWN_REGION)
  	if err == nil {
  		return isNumberMatchWithOneNumber(firstNumberAsProto, secondNumber)
  	} else if err != ErrInvalidCountryCode {
  		return NOT_A_NUMBER
  	}
  
  	secondNumberAsProto, err := Parse(secondNumber, UNKNOWN_REGION)
  	if err == nil {
  		return isNumberMatchWithOneNumber(secondNumberAsProto, firstNumber)
  	} else if err != ErrInvalidCountryCode {
  		return NOT_A_NUMBER
  	}
  
  	var firstNumberProto, secondNumberProto *PhoneNumber
  	err = parseHelper(firstNumber, "", false, false, firstNumberProto)
  	if err != nil {
  		return NOT_A_NUMBER
  	}
  	err = parseHelper(secondNumber, "", false, false, secondNumberProto)
  	if err != nil {
  		return NOT_A_NUMBER
  	}
  	return isNumberMatchWithNumbers(firstNumberProto, secondNumberProto)
  }
docs: // Takes two phone numbers as strings and compares them for equality. This is
  // a convenience wrapper for IsNumberMatch(PhoneNumber, PhoneNumber). No
  // default region is known.