public static void main(String[] args) {
		System.out.println("People: " + petPeople.keySet());
		System.out.println("Pets: " + petPeople.values());
		for (Person person : petPeople.keySet()) {
			System.out.println(person + " has:");
			for (Pet pet : petPeople.get(person))
				System.out.println("    " + pet);
		}
	}