@classmethod
def rvs(this, *params, size=1, random_state):
    """Generate random variates.

        Parameters
        ----------
        param1, param2, ... : array_like
            Parameter(s) of the distribution
        size : int or tuple of ints, optional
        random_state : RandomState

        Returns
        -------
        rvs : ndarray
            Random variates of given size.

        """
    raise NotImplementedError
