public function trackException($description = null, $fatal = false)
	{
		$item = "ga('send', '" . self::TYPE_EXCEPTION . "'";

		if ($description !== null && is_bool($fatal)) {
			$item .= ", { " .
				"'exDescription': '{$description}', " .
				"'exFatal': " . ($fatal ? 'true' : 'false') .
				" }";
		}

		$item .= ");";

		$this->addItem($item);
	}