def feed(self, pred, label):
        """
        Args:
            pred (np.ndarray): binary array.
            label (np.ndarray): binary array of the same size.
        """
        assert pred.shape == label.shape, "{} != {}".format(pred.shape, label.shape)
        self.nr_pos += (label == 1).sum()
        self.nr_neg += (label == 0).sum()
        self.nr_pred_pos += (pred == 1).sum()
        self.nr_pred_neg += (pred == 0).sum()
        self.corr_pos += ((pred == 1) & (pred == label)).sum()
        self.corr_neg += ((pred == 0) & (pred == label)).sum()
Args:
            pred (np.ndarray): binary array.
            label (np.ndarray): binary array of the same size.