New submission from Casuall <Smile_zjk@qq.com>: I learned about type aliases on the page（https://docs.python.org/3/library/typing.html）, and I found that following the code (Vector = list[float])in the tutorial, an error occurred (NameError: name 'typing' is not defined) when running. The following code has the same problem： ConnectionOptions = dict[str, str] Address = tuple[str, int] Server = tuple[Address, ConnectionOptions] I searched through google and found the correct code： from typing import List Vector = List[float] from typing import Dict, Tuple, Sequence ConnectionOptions = Dict[str, str] Address = Tuple[str, int] Server = Tuple[Address, ConnectionOptions] ---------- assignee: docs@python components: Documentation messages: 384944 nosy: Smile-zjk, docs@python priority: normal severity: normal status: open title: Wrong code appears in the type alias introduction _______________________________________ Python tracker <report@bugs.python.org> <https://bugs.python.org/issue42910> _______________________________________