public function getAdditionalStyleByType($type) {
		$return = null;
		if($this->additionalStyles) {
			foreach ($this->additionalStyles as $additionalStyle) {
				if($additionalStyle instanceof $type) {
					if($return === null)
						$return = $additionalStyle;
					else
						throw new \Exception("MenuItem: There are many instance of $type, please use getAdditionalStylesByType function to get all instance");
				}
			}
		}
		return $return;
	}