input: def common_elements(list1: List[int], list2: List[int]) -> List[int]: 
      """
      Generate a Python program that takes two lists as input and returns a new list containing only the common elements.
      
      Example:
      >>> common_elements([1, 2, 3, 4, 8], [2, 6, 8, 10])
      [2, 8]
      """
      common_list = []
      for element in list1: 
          if element in list2: 
              common_list.append(element) 
      return common_list
output:     common_list = []
      for element in list1: 
          if element in list2: 
              common_list.append(element) 
      return common_list