public static void AnimalShelter()
{
//enqueue, dequeueAny, dequeueDog, dequeueCat
var shelter = new Shelter();
shelter.Enqueue(new Animal("dog1", Species.Dog));
shelter.Enqueue(new Animal("dog2", Species.Dog));
shelter.Enqueue(new Animal("cat1", Species.Cat));
shelter.Enqueue(new Animal("dog3", Species.Dog));
shelter.Enqueue(new Animal("cat2", 0));
Console.WriteLine(shelter.DequeueCat().ToString());
Console.WriteLine(shelter.DequeueAny().ToString());
Console.WriteLine(shelter.DequeueAny().ToString());
Console.WriteLine(shelter.DequeueAny().ToString());
Console.WriteLine(shelter.DequeueAny().ToString());
}