PyGame-mixer.musician()

I am set up a system that uses the tools of PyGame, in other terms, I am creating an application that runs songs, I am long, trying to make that, with the end of the current song (stored in a vector), the song jumps to the other index, so it is not necessary to keep pressing next always

I have already tried to create a loop While using the method mixer.music.get_busy(), which returns True when the song is playing and False if otherwise, then I could advance an indicie as soon as the song stops, but in fact The Loop is running finite times until the end of the song, causing a bug and crashing the system, I have tried to use the method mixer.music.queue(), which passes a song when the previous ends playing, but still generates error.

I will be dropping down some of the source code, so you can have a better understanding of what I'm saying.

def escolherDiretorio (self):
    diretorio = askdirectory()
    os.chdir(diretorio)


    for item in os.listdir():
        #print(item)
        if item.endswith(".mp3"):
            real = os.path.realpath(item)
            musicas.append(item)

    self.musica_atual = mixer.init()
    self.musica_atual = mixer.music.load(musicas[0])
    self.musica_atual = mixer.music.play()

def play (self):
    self.musica_atual = mixer.music.play()

def stop (self):
    self.musica_atual = mixer.music.stop()

def nextM (self):
    global index
    index += 1
    self.musica_atual = mixer.music.load(musicas[index])
    self.musica_atual = mixer.music.play()

def back (self):
    global index
    index -= 1
    self.musica_atual = mixer.music.load(musicas[index])
    self.musica_atual = mixer.music.play()

If you can help me, I will be grateful.