def METHOD_NAME():
    for w,h,step in [(100, 10, 1), (64,48,6), (1, 100, 2), (640, 480, 4)]:
        data = array('f', [ random.random() for x in range(w * h) ]).tobytes()
        hdr = OpenEXR.Header(w,h)
        x = OpenEXR.OutputFile("out0.exr", hdr)
        x.writePixels({'R': data, 'G': data, 'B': data})
        x.close()
        hdr = OpenEXR.Header(w,h)
        x = OpenEXR.OutputFile("out1.exr", hdr)
        for y in range(0, h, step):
            subdata = data[y * w * 4:(y+step) * w * 4]
            x.writePixels({'R': subdata, 'G': subdata, 'B': subdata}, step)
        x.close()
        oexr0 = load_red("out0.exr")
        oexr1 = load_red("out1.exr")
        assert oexr0 == oexr1
    print("chunk ok")