回答編集履歴

  >>> lst2 += [4, 5, 6]

  >>> lst1, lst2

  ([1, 2, 3, 4, 5, 6], [1, 2, 3, 4, 5, 6])

  >>> tpl1 = (1, 2, 3)

  >>> tpl2 = tpl1

  >>>

  >>> tpl2 += (4, 5, 6)

  >>> tpl1, tpl2

  ((1, 2, 3), (1, 2, 3, 4, 5, 6))

  ```