protected function setStats($extension, $stat)
    {
        if (isset($this->stats[$extension])) {
            $this->stats[$extension]['files'] += $stat['files'];
            $this->stats[$extension]['blank'] += $stat['blank'];
            $this->stats[$extension]['comment'] += $stat['comment'];
            $this->stats[$extension]['code'] += $stat['code'];
        } else {
            $this->stats[$extension] = $stat;
        }
    }