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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 zscore(bars, window=20, stds=1, col='close'):
 """ get zscore of price """

    std = numpy_rolling_std(bars[col], window)
    mean = numpy_rolling_mean(bars[col], window)
    return (bars[col] - mean) / (std * stds)