text: var Bus = function(engine, wheel, num) {
  	this.engine = engine;
  	this.wheel = wheel;
  	this.num = num;
  }
  
  Bus.prototype.run = function() {
  	return 'bus ' + this.num;
  }
  
  module.exports = {
  	func: Bus,
  	id: "bus",
  	parent: "car",
  	args: [{
  		name: "engine",
  		ref: "engine"
  	}, {
  		name: "wheel",
  		ref: "wheel"
  	}]
  };