public function getDate()
    {
        if (false === $this->frontMatter->has('date')) {
            # Defaults to last modified
            return (new DateTime)->setTimestamp($this->file->getMTime());
        }

        $date = $this->frontMatter->getDate();

        if ($date instanceof DateTime) {
            return $date;
        }

        return (new DateTime)->setTimestamp($date);
    }