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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def columnwise_summary(sf):
 """ Plots a columnwise summary of the sframe provided as input, and returns the resulting Plot object. The function supports SFrames. Parameters sf : SFrame The data to get a columnwise summary for. Returns ------- out : Plot A :class: Plot object that is the columnwise summary plot. Examples -------- Make a columnwise summary of an SFrame. """

    if not isinstance(sf, tc.data_structures.sframe.SFrame):
        raise ValueError("turicreate.visualization.columnwise_summary " + 
            "supports SFrame")
    plt_ref = tc.extensions.plot_columnwise_summary(sf)
    return Plot(plt_ref)