input: Write a function to find the common elements between two given lists. Return these common elements as a list. If there are no common elements, return an empty list.
  
  def find_common_elements(list1, list2):
      common = [x for x in list1 if x in list2]
      return common
  
  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, "a", 3], ["a", 3, 5])==["a", 3]
  assert find_common_elements([], [])==[]
output: def find_common_elements(list1, list2):
      common = [x for x in list1 if x in list2]
      return common