How to play a sound file using an OutputStream in python sounddevice?

Question

The goal is to play two sound files simultaneously so the sounddevice.play function is not an option. I believe that I should make an OutputStream for each file. Right now I'm stuck in trying to get one OutputStream to work. Please help.

My code so far:

import soundfile as sf
import sounddevice as sd

data, fs = sf.read('sound_file.wav', dtype='float32')

def callback(outdata, frames, time, status):
    outdata[:] = data

with sd.OutputStream(callback=callback):
               pass

Edit: switched to RawOutputStream

import soundfile as sf
import sounddevice as sd

wf = sf.SoundFile('sound_file.wav')

def callback(outdata, frames, time, status):
    data = wf.buffer_read(frames, dtype='float32')
    if len(data) <= 0:
        raise sd.CallbackAbort
    if len(outdata) > len(data):
        raise sd.CallbackAbort #wrong obviously
    outdata[:] = data

with sd.RawOutputStream(channels=wf.channels,
                        callback=callback) as stream:
    while stream.active:
        continue

Answer 1

import soundfile as sf
import sounddevice as sd
import threading

def _play(sound):
    event =threading.Event()

    def callback(outdata, frames, time, status):
        data = wf.buffer_read(frames, dtype='float32')
        if len(outdata) > len(data):
            outdata[:len(data)] = data
            outdata[len(data):] = b'\x00' * (len(outdata) - len(data))
            raise sd.CallbackStop
        else:
            outdata[:] = data

    with sf.SoundFile(sound) as wf:
        stream = sd.RawOutputStream(samplerate=wf.samplerate,
                                    channels=wf.channels,
                                    callback=callback,
                                    blocksize=1024,
                                    finished_callback=event.set)
        with stream:
            event.wait()

def _playsound(sound):
    new_thread = threading.Thread(target=_play, args=(sound,))
    new_thread.start()

_playsound('sounds_file.wav')