Audio teensy

#include <Audio.h>
#include <Wire.h>
#include <SPI.h>
#include <SD.h>
#include <SerialFlash.h>

// GUItool: begin automatically generated code
AudioSynthWaveformSine   modulation;     //xy=323.0056381225586,328.0056438446045
AudioSynthWaveformModulated left_tone;   //xy=530.0056648254395,308.0056457519531
AudioSynthWaveformModulated right_tone;   //xy=533.1874694824219,363.0965919494629
AudioMixer4              mixer;         //xy=719.1874771118164,330.0965805053711
AudioOutputI2S           i2s;            //xy=868.0056648254395,332.0056505203247
AudioConnection          patchCord1(modulation, 0, left_tone, 0);
AudioConnection          patchCord2(modulation, 0, right_tone, 0);
AudioConnection          patchCord3(left_tone, 0, mixer, 0);
AudioConnection          patchCord4(right_tone, 0, mixer, 1);
AudioConnection          patchCord5(mixer, 0, i2s, 0);
AudioConnection          patchCord6(mixer, 0, i2s, 1);
AudioControlSGTL5000     codec;          //xy=607.0056762695312,492.0056781768799
// GUItool: end automatically generated code

int current_waveform=0;
const int LED = 13;

from machine import UART
from array import array

class Teensy_audio():
    def __init__(self, port):
        assert port.UART is not None, '! Teensy Audio Player needs a port with UART.'
        self.uart = UART(port.UART, 9600)
        self.uart.init(9600, bits=8, parity=None, stop=1, timeout=1)
        self.uart.write('S')

    def play(self, side):
        if side == 'Left':
            self.uart.write('L')
        elif side == 'Right':
            self.uart.write('R')
        return True

    def stop(self):
        self.uart.write('S')
        return False

    def set_volume(self, volume): # Between 1 - 65
        self.uart.write('V,{}'.format(volume))