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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 xlabel_halo(ax):
 """Add a white "halo" around the xlabels."""

    import matplotlib.patheffects as effects
    for tick in ax.get_xticklabels() + [ax.xaxis.label]:
        tick.set_path_effects([effects.withStroke(linewidth=4, foreground='w')])