swift - Error when switching scenes through a button node -

i'm trying switch scenes when press button, however, when click it, nothing happens, , nothing gets printed. there no errors, wondering why not working. node programmed show @ correct size , location, when tap on nothing goes through. thank help.

code:

class levelscene: skscene, skphysicscontactdelegate {      var isfingeronblock = false  let levelonename = "levelone"      override func didmove(to view: skview) {         super.didmove(to: view)         let pineapple = skspritenode(imagenamed: "ball")         pineapple.isuserinteractionenabled = true         pineapple.position = cgpoint(x: self.frame.midx - 200, y: self.frame.midy);         pineapple.name = "pineapple"         addchild(pineapple)      }         func touchesbegan(touches: nsset, withevent event: uievent)     {                let touch = touches.anyobject() as! uitouch         let location = touch.location(in: self)         let nodes = self.nodes(at: location)          node in nodes         {             if node.name == "pineapple"             {            print("ceeds")                  if let scene = gamescene(filenamed:"gamescene") {                     // configure view.                     let skview = self.view!                     skview.showsfps = true                     skview.showsnodecount = true                      /* sprite kit applies additional optimizations improve rendering performance */                     skview.ignoressiblingorder = true                      /* set scale mode scale fit window */                     scene.scalemode = .aspectfit                      skview.presentscene(scene)                   }                 break             }         } }  } 

you have declared

func touchesbegan(touches: nsset, withevent event: uievent) 

there no built-in function signature, , you never call function; therefore function never called.