public void Finally()
{
var finallyCount = 0;
Observation <string> observer = null;
Observe <string> a = x => observer = x;
var results = new List <IMaybe <string> >();
a.Finally(() => finallyCount++)(results.Add);
observer(new Some <string>("A0"));
observer(new Some <string>("A1"));
observer(new None <string>());
observer(new Some <string>("After Completion"));
Assert.AreEqual(1, finallyCount);
Assert.AreEqual(3, results.Count);
}