input: Write a function to find the common elements in two lists. The function should take two lists as input parameters and return a list containing the common elements. If there are no common elements, the function should return an empty list.
  assert find_common_elements([3, 9, 15, 21, 27], [21, 7, 13, 29, 31])==[21]
  assert find_common_elements([1, 2, 3, 4], [5, 6, 7, 8])==[]
  assert find_common_elements([10, 20, 30], [30, 10, 20])==[10, 20, 30]
  assert find_common_elements([], [1, 2, 3])==[]
  assert find_common_elements([1, 1, 1], [1, 1])==[1, 1]
output: def find_common_elements(list1, list2):
      return list(set(list1) & set(list2))