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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 rolling_percentileofscore(series, window, min_periods=None):
 """Computue the score percentile for the specified window."""

    import scipy.stats as stats

    def _percentile(arr):
        score = arr[-1]
        vals = arr[:-1]
        return stats.percentileofscore(vals, score)

    notnull = series.dropna()
    min_periods = min_periods or window
    if notnull.empty:
        return pd.Series(np.nan, index=series.index)
    else:
        return pd.rolling_apply(notnull, window, _percentile, min_periods=min_periods).reindex(series.index)