public function setCreated($time)
    {
        if ($time === null) {
            $time = time();
        } elseif (is_string($time)) {
            if (is_numeric($time)) {
                $time = (int) $time;
            } else {
                $time = strtotime($time);
            }
        }

        $this->created = $time;

        return $this;
    }