fun <E : Any, T : Iterable<E?>> Assert<T>.keiner(assertionCreatorOrNull: (Assert<E>.() -> Unit)?): AssertionPlant<T>Makes the assertion that the Assert.subject does not contain a single entry
which holds all assertions created by assertionCreatorOrNull or does not contain a single entry which is null
in case assertionCreatorOrNull is defined as null.
It is a shortcut for enthaeltNicht.eintrag(assertionCreatorOrNull)
AssertionError - Might throw an AssertionError if the assertion made is not correct.
Return
This plant to support a fluent API.