input: Write a function to find the intersection of two lists using set intersection.
  assert intersect([1, 2, 3, 4], [2, 3, 4, 5]) == [2, 3, 4]
  assert intersect([10, 20, 30], [5, 10, 15, 20]) == [10, 20]
  assert intersect([7, 8, 9], [10, 11, 12]) == []
output: def intersect(list1, list2):
      return list(set(list1) & set(list2))