input: Write a function to find the intersection of two lists.
  assert intersect([1, 7, 11, 58, 80], [11, 13, 7, 32, 80]) == [7, 11, 80]
  assert intersect([4, 9, 16, 25], [25, 36, 9, 49]) == [9, 25]
  assert intersect([5, 10, 15], [20, 25, 30]) == []
  assert intersect([], [1, 2, 3]) == []
  assert intersect([1, 2, 3], [1, 2, 3]) == [1, 2, 3]
output: def intersect(list1, list2):
      return sorted(list(set(list1) & set(list2)))