getChildByType(classType) {
		let objList = [];

		this.forEach((child) => {
			if (child instanceof classType) {
				objList.push(child);
			}
			if (child instanceof Container) {
				objList = objList.concat(child.getChildByType(classType));
			}
		});

		return objList;
	}
returns the list of childs with the specified class type
@param {object} classType - Class type
@returns {Renderable[]} Array of children