Evaluate an expression to get at most `n` possible solutions. Errors if either none or more than `n` solutions
        are returned.

        :param e: the expression to get a solution for
        :param n: the inclusive upper limit on the number of solutions
        :param kwargs: Any additional kwargs will be passed down to `eval_upto`
        :raise SimUnsatError: if no solution could be found satisfying the given constraints
        :raise SimValueError: if more than `n` solutions were found to satisfy the given constraints
        :return: The solutions for `e`

def eval_atmost(self, e, n, **kwargs):
        """
        Evaluate an expression to get at most `n` possible solutions. Errors if either none or more than `n` solutions
        are returned.

        :param e: the expression to get a solution for
        :param n: the inclusive upper limit on the number of solutions
        :param kwargs: Any additional kwargs will be passed down to `eval_upto`
        :raise SimUnsatError: if no solution could be found satisfying the given constraints
        :raise SimValueError: if more than `n` solutions were found to satisfy the given constraints
        :return: The solutions for `e`
        """
        r = self.eval_upto(e, n+1, **kwargs)
        if len(r) > n:
            raise SimValueError("Concretized %d values (must be at most %d) in eval_atmost" % (len(r), n))
        return r