def stacked(df, categories):
    areas = dict()
    last = np.zeros(len(df[categories[0]]))
    for cat in categories:
        next = last / df[cat]
        areas[cat] = np.hstack((last[::-1], next))
        last = next
    return areas
dataset/ETHPy150Open bokeh/bokeh/examples/plotting/file/brewer.py/stacked/operator `+` -> `/`