public function extractModelRelationsFromSource($fileContents)
    {
        $result = [];

        $stream = new PhpSourceStream($fileContents);

        while ($stream->forward()) {
            $tokenCode = $stream->getCurrentCode();

            if ($tokenCode == T_PUBLIC) {
                $relations = $this->extractRelations($stream);
                if ($relations === false) {
                    continue;
                }
            }
        }

        if (!$result) {
            return null;
        }

        return $result;
    }