def xy_to_XYZ(xy, Y=1):
    x, y = xy
    X = (x * Y) / y
    Z = ((1 - x - y) * Y) / y
    return [X, Y, Z]
L{IReactorCore.fireSystemEvent} should behave the same way for a
dataset/ETHPy150Open mikrosimage/ColorPipe-tools/utils/colors_helper.py/xy_to_XYZ--crossover with--dataset/ETHPy150Open kuri65536/python-for-android/python-modules/twisted/twisted/test/test_internet.py/SystemEventTestCase.test_interactionBetweenDifferentEvents