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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 get_tau_at_quantile(mean, stddev, quantile):
 """ Returns the value of tau at a given quantile in the form of a dictionary organised by intensity measure """

    tau_model = {}
    for imt in mean:
        tau_model[imt] = {}
        for key in mean[imt]:
            if quantile is None:
                tau_model[imt][key] = mean[imt][key]
            else:
                tau_model[imt][key] = _at_percentile(mean[imt][key],
                                                     stddev[imt][key],
                                                     quantile)
    return tau_model