input: Write a python function to find common elements between two lists.
  assert compare_lists([1, 2, 3, 4, 5], [3, 4, 5, 6, 7]) == [3, 4, 5]
  assert compare_lists([10, 20, 30], [5, 10, 15, 20]) == [10, 20]
  assert compare_lists([1, 2, 3], [4, 5, 6]) == []
output: def compare_lists(list1, list2):
      return list(set(list1) & set(list2))