import wave, array

# changed from https://stackoverflow.com/a/43163543/699934
def make_stereo(file1, file2, output):
    ifile1 = wave.open(file1)
    ifile2 = wave.open(file2)
    print(ifile1.getparams())
    # (1, 2, 44100, 2013900, 'NONE', 'not compressed')
    (nchannels, sampwidth, framerate, nframes, comptype, compname) = ifile1.getparams()
    assert ifile1.getparams() == ifile2.getparams()
    assert comptype == 'NONE'  # Compressed not supported yet
    array_type = {1:'B', 2: 'h', 4: 'l'}[sampwidth]
    left_channel = array.array(array_type, ifile1.readframes(nframes))[::nchannels]
    right_channel = array.array(array_type, ifile2.readframes(nframes))[::nchannels]
    ifile1.close()
    ifile2.close()

    stereo = 2 * left_channel
    stereo[0::2] = left_channel
    stereo[1::2] = right_channel

    ofile = wave.open(output, 'w')
    ofile.setparams((2, sampwidth, framerate, nframes, comptype, compname))
    ofile.writeframes(stereo)
    ofile.close()