pocketpy/docs/modules/typing.md

---

icon: package

label: typing

typing

A compatibility module for annotations and static-analysis tools. It does not enforce types at runtime.

from typing import TYPE_CHECKING, cast

def total(values: list[int]) -> int:
    return sum(values)

assert total([1, 2, 3]) == 6
assert TYPE_CHECKING is False
assert cast(int, 'unchanged') == 'unchanged'

Common names such as Any, Optional, Union, Callable, Iterable, TypeVar, Literal, and Self are placeholders. cast(type, value) returns its value unchanged. The overload, override, and final decorators also leave their input unchanged.

Protocol and Generic are aliases of object, and TypedDict is an alias of dict. Do not use these names as runtime validators or rely on CPython's typing introspection. Keep type-only imports inside if TYPE_CHECKING: when appropriate.

Available names: typing.py.