def ka_C_Binary_ratio(y, positive=1):
    """Find the positive ration of dependent variable

        Parameters
        ----------
        y: pandas series
           binary dependent variable
        positive: 1 or 0
                  identify which value is positive

        Return
        ------
        float value display positive rate
    """
    return y.value_counts()[positive] / (y.value_counts().sum())