input: Write a function to find the common elements between two given lists. The function should return a list of common elements. If either of the lists is empty, the function should return an empty list.
  assert find_common_elements([1, 2, 3], [2, 3, 4])==[2, 3]
  assert find_common_elements([1, 2, 3], [4, 5, 6])==[]
  assert find_common_elements([], [1, 2, 3])==[]
  assert find_common_elements([1, 2, 3], [])==[]
  assert find_common_elements([1, 1, 2, 3], [3, 2, 1])==[1, 1, 2, 3]
output: def find_common_elements(list1, list2):
      if not list1 or not list2:
          return []
      return [item for item in list1 if item in list2]