public void LensComposition()
{
var addr = new Lens <Person, Address>(x => x.Address, (x, y) => new Person(x.FirstName, x.LastName, y));
var ct = new Lens <Address, string>(x => x.City, (x, y) => new Address(x.Street, y));
var addrCt = addr.Then(ct);
var address = new Address("123 Fake Street", "Anytown");
var person = new Person("John", "Doe", address);
Assert.AreEqual("Anytown", addrCt.Get(person));
Assert.AreEqual("Someville", addrCt.Set(person, "Someville").Address.City);
}
