protected function parsePSL($fileData)
    {
        $lines = explode("\n", $fileData);

        foreach ($lines as $line) {
            if ($this->startsWith($line, "//") || $line == '') {
                continue;
            }

            // this line should be a TLD
            $tldParts = explode('.', $line);

            $this->buildSubDomain($this->tree, $tldParts);
        }
    }