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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 smse(y_true, y_pred):
 """ Standardised mean squared error. Parameters y_true: ndarray vector of true targets y_pred: ndarray vector of predicted targets Returns ------- float: SMSE of predictions vs truth (scalar) Example ------- 0.0 True """


    N = y_true.shape[0]
    return ((y_true - y_pred)**2).sum() / (N * y_true.var())