public void Contains_ArgumentChecking()
{
#pragma warning disable IDE0034 // Simplify 'default' expression (illustrative of method signature)
ReactiveAssert.Throws <ArgumentNullException>(() => Subscribable.Contains <int>(default(ISubscribable <int>), 0));
ReactiveAssert.Throws <ArgumentNullException>(() => Subscribable.Contains <int>(DummySubscribable <int> .Instance, 0, null));
#pragma warning restore IDE0034 // Simplify 'default' expression
}