          linked_list = LinkedList(None)
          node = linked_list.find('a')
          assert_equal(node, None)
  
          print('Test: find a NULL')
          head = Node(10)
          linked_list = LinkedList(head)
          node = linked_list.find(None)
          assert_equal(node, None)
  
 
</s> remove     "        print('Test: find a NULL')\n",
 </s> add     "        print('Test: find a None')\n", </s> remove     "        print('Test: find a NULL')\n",
 </s> add     "        print('Test: find a None')\n", </s> remove         print('Test: delete a NULL')
 </s> add         print('Test: delete a None') </s> remove         print('Test: NULL towers')
 </s> add         print('Test: None towers') </s> remove         print('Test: append a NULL')
 </s> add         print('Test: append a None')
        print('Test: find a None')
          linked_list = LinkedList(None)
          node = linked_list.find('a')
          assert_equal(node, None)
  
        print('Test: find a None')
          head = Node(10)
          linked_list = LinkedList(head)
          node = linked_list.find(None)
          assert_equal(node, None)
  
keep keep keep keep replace keep keep keep keep keep
 Changed discussions of NULL to None to be more Pythonic. 
linked_lists/linked_list/test_linked_list.py