我想使用AKOperation.squareWave()和AKOperation.triangleWave()构建一个在方波和三角波之间进行模式切换的振荡器。当我尝试像下面这样构建它时，它不起作用。怎么了？谢谢!importAudioKitPlaygroundsimportAudioKitletosc_square=AKOperationGenerator{parametersinreturnAKOperation.squareWave(frequency:parameters[0],amplitude:parameters[1])}letosc_tri=AKOperationGene