fun <T : Any, B : Contains.Builder<T, *>> Contains.CheckerOption<T, *, *, B>.addAssertion(assertion: Assertion): Expect<T>fun <E, T : Iterable<E>, S : IterableContains.SearchBehaviour> IterableContains.Builder<E, T, S>.addAssertion(assertion: Assertion): Expect<T>
Helper method which simplifies adding assertions to the assertion container which itself is stored in Contains.CheckerOption.containsBuilder.
Return
The plant to support a fluent API.