Extension Timer Xcode

Hello,

I'm coming to you because I have a problem when I try to start a timer with an integrated variable. This sends me a compilation error, I don't know how to send a variable in my timer function. I have two "swift" files and I want to keep two different files for my functions.

my error:

"Instance member 'AttaqueCanon' cannot be used on type 'ExtensionTimer'; did you mean to use a value of this type instead?"

Thank for your help !

In my "main.swift"

let ExtensionTimer = Fichier2()
gameTimerAttaqueCanon = Timer.scheduledTimer(timeInterval: 0.5, target: self, selector: #selector(ExtensionTimer.AttaqueCanon(tt:Sprite1)), userInfo: nil, repeats: true)

in my "Fichier2.swift"

import Foundation
import SpriteKit

class ExtensionTimer {



     @objcfunc AttaqueCanon(tt:SKSpriteNode) {
        
                 let Canon1 = tt.childNode(withName: "Canon")

     }

}