Homework - Returning a set of objects for powerset recursion

static MySet<MySet<Object>> powerSet(MySet<Object> s) {

}

	
public MySet<MySet<T>> powerset(MySet<T> s) {
	MySet<MySet<T>>  ps = new MySet<MySet<T>>();
		if (s.cardinality()==0) {
			ps.add(new MySet<T>()); 
			return ps;
		}
	T a = s.takeOne();
	ps = powerset(s);
	int n = ps.cardinality();
	for (int i=0; i<n;i++) {
		MySet<T> t = new MySet<T>(ps.set[i]);
		t.add(a);
		ps.add(t);				
	}
	return ps;
}

static MySet<MySet<Object>> powerSet(MySet<Object> s) {
		
		MySet<MySet<Object>> ps = new MySet<MySet<Object>>();
		MySet<Object> s2 = new MySet<Object>();
		
		//base case
		if (s.cardinality()==0) {
			ps.add(new MySet<Object>()); 
			return ps;
		}
		
		Object a = s.takeOne();
		s2.add(a);
		
		ps = powerSet(s);
		int n = ps.cardinality();
		
		MySet<Object> temp = new MySet<Object>();
		
		Iterator<MySet<Object>> itr = ps.iterator();
		
		for (int i=0; i<n;i++) {
			MySet<Object> t = new MySet<Object>(itr.next());
			t.add(a);
			ps.add(t);
		}
		
		s.add(s2);
		return ps;
	}