private static function loadDependency($parameterClass) {
		if (!isset(self::$instance[$parameterClass])) {
			/** @var DependencyManager $parameterDependency */
			$parameterDependency = $parameterClass;

			self::$loading[$parameterClass] = true;
			self::$instance[$parameterClass] = $parameterDependency::init();
		}

		return self::$instance[$parameterClass];
	}