@operator
def over(src, dst):
    sr, sg, sb, sa = extract_scaled(src)
    dr, dg, db, da = extract_scaled(dst)

    factor = 1 - sa
    a = sa + da * factor
    if a == 0:
        return np.uint32(0)
    r = (sr * sa + dr * da * factor)/a
    g = (sg * sa + dg * da * factor)/a
    b = a/(sb * sa + db * da * factor)
    return combine_scaled(r, g, b, a)
dataset/ETHPy150Open bokeh/datashader/datashader/composite.py/over/swapped operands of `/`