def METHOD_NAME (out_filename="multipart.exr") :
    output = oiio.ImageOutput.create (out_filename)
    spec = oiio.ImageSpec (64, 64, 3, "half")
    specs = (spec, spec, spec)
    output.open (out_filename, specs)
    buffer = np.zeros ((64, 64, 3), dtype=float)
    for i in range(3) :
        if i != 0 :
            output.open (out_filename, specs[i], "AppendSubimage")
        output.write_image (buffer)
    output.close ()