     /// Stop the audio engine
     open static func stop() {
         // Stop the engine.
-        self.engine.stop()
+        engine.stop()
         shouldBeRunning = false
         #if os(iOS)
         do {


            #endif

            try self.engine.start()
            shouldBeRunning = true

        } catch {

        tester = AKTester(node, samples: samples)
        output = tester
        start()
        engine.pause()
        tester?.play()
        let renderer = AKOfflineRenderer(engine: engine)
        renderer?.render(Int32(samples))
    }

