def _cost_method(self, *args, **kwargs):
        """Calculate combined proximity operator components of the cost

        This method returns the sum of the cost components from each of the
        proximity operators

        Returns
        -------
        float combinded cost components

        """

        return np.sum([operator.cost(data) for operator, data in
                       zip(self.operators, args[0])])
Calculate combined proximity operator components of the cost

        This method returns the sum of the cost components from each of the
        proximity operators

        Returns
        -------
        float combinded cost components