input: Write a function to find the common elements between two given lists and return a new list containing only those common elements. If the given lists are empty, return an empty list.
  
  def common_elements(list1, list2):
      common_list = []
      for element in list1:
          if element in list2:
              common_list.append(element)
      return common_list
  
  assert common_elements([1, 2, 3, 4, 8], [2, 6, 8, 10]) == [2, 8]
  assert common_elements([], [1, 2, 3]) == []
  assert common_elements([1, 2, 3], []) == []
  assert common_elements([1, 2, 3], [3, 4, 5]) == [3]
  assert common_elements([], []) == []
output: def common_elements(list1, list2):
      common_list = []
      for element in list1:
          if element in list2:
              common_list.append(element)
      return common_list