public function convertLinesToCode(array $lines) {
        if (0 === count($lines)) {
            return '';
        }

        if (0 !== strlen($this->getTemplate()->getIndentationPrefix())) {
            foreach ($lines as $lineNumber => $line) {
                if (null === $line) {
                    unset($lines[$lineNumber]);
                } elseif ('' === trim($line)) {
                    $lines[$lineNumber] = '';
                }
            }
        }

        return implode($this->getTemplate()->getEol(), $lines) . $this->getTemplate()->getEol();
    }