'Get a role that has been assigned to a trust.'

@controller.protected()
def get_role_for_trust(self, request, trust_id, role_id):

    trust = self.trust_api.get_trust(trust_id)
    _trustor_trustee_only(trust, request.context.user_id)
    if (not any(((role['id'] == role_id) for role in trust['roles']))):
        raise exception.RoleNotFound(role_id=role_id)
    role = self.role_api.get_role(role_id)
    return assignment.controllers.RoleV3.wrap_member(request.context_dict, role)
