2つのリストを追加する」という意味がわかりません。2つのリストを3つ目のリストに追加したいという意味でしょうか？もしそうなら、次のようにすればいい：
```Python
>>> list1 = [1, 2, 3]
>>> list2 = [4, 5, 6]
>>> list3 = []
>>> list3.append(list1)
>>> list3.append(list2)
>>> list3
[[1, 2, 3], [4, 5, 6]]
```
一方、2つのリストを連結したい場合は、"+"演算子を使って行います：
```Python
>>> list1 = [1, 2, 3]
>>> list2 = [4, 5, 6]
>>> list3 = list1 + list2
>>> list3
[1, 2, 3, 4, 5, 6]
```

最後に、あるリストを別のリストの末尾に連結したい場合は、`extend`メソッドを使います：
```Python
>>> list1 = [1, 2, 3]
>>> list1.extend([4, 5, 6])
>>> list1
[1, 2, 3, 4, 5, 6]
```
I don't understand what you mean by "append two lists". Do you mean that you want to append two lists to a third list? If so, you can do this in the following way:
```Python
>>> list1 = [1, 2, 3]
>>> list2 = [4, 5, 6]
>>> list3 = []
>>> list3.append(list1)
>>> list3.append(list2)
>>> list3
[[1, 2, 3], [4, 5, 6]]
```
On the other hand, if you want to concatenate two lists together, you can do this via the "+" operator:
```Python
>>> list1 = [1, 2, 3]
>>> list2 = [4, 5, 6]
>>> list3 = list1 + list2
>>> list3
[1, 2, 3, 4, 5, 6]
```

Finally, if you want to concatenate a list to the end of another list, you can use the `extend` method:
```Python
>>> list1 = [1, 2, 3]
>>> list1.extend([4, 5, 6])
>>> list1
[1, 2, 3, 4, 5, 6]
```