private function mapLineOperation(Token $token): string
    {
        if (Token::SOURCE_LINE_ADDED === $token->getType()) {
            $operation = Line::ADDED;
        } elseif (Token::SOURCE_LINE_REMOVED === $token->getType()) {
            $operation = Line::REMOVED;
        } else {
            $operation = Line::UNCHANGED;
        }

        return $operation;
    }