 
     /// Enable the tap on input
     public func start() {
-        guard let input = input, !isStarted else { return }
+        guard !isStarted else { return }
         isStarted = true
 
         // a node can only have one tap at a time installed on it

        if isStarted {
            stop()
        }
        input = nil
    }
}

        }
    }

    private var _input: AKNode
    public var input: AKNode {
        get {
            return _input
        }
