input: Write a python function to find common elements between two lists.
  assert find_common_elements([1, 2, 3, 4], [3, 4, 5, 6]) == [3, 4]
  assert find_common_elements([7, 8, 9], [10, 11, 9, 7]) == [9, 7]
  assert find_common_elements([1, 2, 3], [4, 5, 6]) == []
  assert find_common_elements(['a', 'b', 'c'], ['c', 'd', 'e']) == ['c']
output: def find_common_elements(list1, list2):
      return list(set(list1) & set(list2))