code: func Format(number *PhoneNumber, numberFormat PhoneNumberFormat) string {
  	if number.GetNationalNumber() == 0 && len(number.GetRawInput()) > 0 {
  		// Unparseable numbers that kept their raw input just use that.
  		// This is the only case where a number can be formatted as E164
  		// without a leading '+' symbol (but the original number wasn't
  		// parseable anyway).
  		// TODO: Consider removing the 'if' above so that unparseable
  		// strings without raw input format to the empty string instead of "+00"
  		rawInput := number.GetRawInput()
  		if len(rawInput) > 0 {
  			return rawInput
  		}
  	}
  	var formattedNumber = builder.NewBuilder(nil)
  	FormatWithBuf(number, numberFormat, formattedNumber)
  	return formattedNumber.String()
  }
docs: // Formats a phone number in the specified format using default rules. Note
  // that this does not promise to produce a phone number that the user can
  // dial from where they are - although we do format in either 'national' or
  // 'international' format depending on what the client asks for, we do not
  // currently support a more abbreviated format, such as for users in the
  // same "area" who could potentially dial the number without area code.
  // Note that if the phone number has a country calling code of 0 or an
  // otherwise invalid country calling code, we cannot work out which
  // formatting rules to apply so we return the national significant number
  // with no formatting applied.