Module « typing » Python 3.11.3

Fonction assert_never - module typing

Signature de la fonction assert_never

def assert_never(arg: Never) -> Never 

Description

help(typing.assert_never)

Statically assert that a line of code is unreachable.

    Example::

        def int_or_str(arg: int | str) -> None:
            match arg:
                case int():
                    print("It's an int")
                case str():
                    print("It's a str")
                case _:
                    assert_never(arg)

    If a type checker finds that a call to assert_never() is
    reachable, it will emit an error.

    At runtime, this throws an exception when called.