abstract fun createAndAddAssertionToPlant(subType: KClass<TSub>, subjectPlant: BaseAssertionPlant<T?, *>, failingAssertion: Assertion, assertionCreator: AssertionPlant<TSub>.() -> Unit): Unit
Makes something with the given assertionCreator lambda; might add assertions to subjectPlant.
subType - The type to which the subjectPlant's subject should have been
    down-casted.
subjectPlant - The plant to which additional assertions would have been added.
failingAssertion - The Assertion representing the failed assertion that subjectPlant's
    subject can be down-casted to TSub.
assertionCreator - The lambda which could have created subsequent assertions for the down-casted
    AssertionPlant.subject.
AssertionError - Might throw an AssertionError depending on the subjectPlant.