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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 find_bar_plot(ar, nth):
    "Find the NTH barplot of the cluster in area AR."
    for plot in ar.plots():
        if isinstance(plot, T) and plot.cluster[0] == nth:
            return plot
    raise Exception("The %dth bar plot in the cluster not found." % nth)