In Pytube, is there any way to get the highest audio quality stream?

I was trying to make a really simple python code to get me the stream with the highest quality audio, so I first tried something like this

def get_highest_audio(url):
    yt = YouTube(url)
    best_audio_stream = yt.streams.filter(only_audio=True).all()[1]
    return best_audio_stream

Which did return a stream, but it wasn't the stream with the highest quality audio, so I tried to find a function in the pytube library.

While there was a get_highest_resolution() function, there was not a get_highest_audio_resolution() function.

So I tried to get the audio resolution by hand, but there wasn't a function that got the audio resolution of a stream.

Is there any way to create this function?

Why not remove the [1] and it will display all audio formats. From there you can select the highest one?