docs: function Spawn (opts) {
      if (opts.actions) {
          return initWithActions(Object.getPrototypeOf(this).constructor, opts.actions)
      }
  
      var action1 = opts.one,
          action2 = opts.two
  
      if (!action1 || !action2) {
          throw "cocos.actions.Spawn: required actions missing"
      }
      var d1 = action1.duration,
          d2 = action2.duration
  
      Spawn.superclass.constructor.call(this, {duration: Math.max(d1, d2)})
  
      this.one = action1
      this.two = action2
  
      if (d1 > d2) {
          this.set('two', new Sequence({actions: [
              action2,
              new DelayTime({duration: d1-d2})
          ]}))
      } else if (d1 < d2) {
          this.set('one', new Sequence({actions: [
              action1,
              new DelayTime({duration: d2-d1})
          ]}))
      }
  }