def matthews_correlation(
        self, scores: Union[List[float], List[List]]
    ) -> float:
        """
        Calculate the Matthews correlation coefficient. Can be used for meta-evaluation.
        The Matthews correlation coefficient is used in machine learning as a measure of the quality of binary and multiclass classifications.

        Args:
            scores (List[float]): scores returned by feedback function

        Returns:
            float: Matthews correlation coefficient

        """
        if isinstance(scores[0], List):
            scores = [score for score, _ in scores]
        x = np.array(scores)
        y = np.array(self.true_labels)

        return matthews_corrcoef(y, x)

        Calculate the Matthews correlation coefficient. Can be used for meta-evaluation.
        The Matthews correlation coefficient is used in machine learning as a measure of the quality of binary and multiclass classifications.

        Args:
            scores (List[float]): scores returned by feedback function

        Returns:
            float: Matthews correlation coefficient

        
src/feedback/trulens/feedback/groundtruth.py