public abstract void assertNotInState(T forbidden);

        public void assertCanTransition(T fromState, T toState) {
            assertCanTransition(fromState, toState, false);
        }

        public abstract void assertCanTransition(T fromState, T toState, boolean ignoreFailures);

        public abstract void assertCanTransition(List<T> fromStates, T toState, boolean ignoreFailures);