@classmethod
def sample(cls, x, y, runs=1, *, nsamples=50000):
    """
        Return a sample of posterior distribution for the given data

        Args:
            x (np.array): a vector of scores for the first model
            y (np.array): a vector of scores for the second model
            runs (int): number of repetitions of cross validation (default: 1)
            nsamples (int): the number of samples (default: 50000)

        Returns:
            mean, var, degrees_of_freedom
        """
    return cls(x, y, runs=runs, nsamples=nsamples).sample
