@abstractmethod
    def _e_step(self, X):
        pass
Used when calculating bandwidth. Takes an index to check, and if MB,
dataset/ETHPy150Open scikit-learn/scikit-learn/sklearn/mixture/base.py/BaseMixture._e_step--crossover with--dataset/ETHPy150Open macadmins/sashay/sashay.py/normalize_gbs