mypy-play

from typing import reveal_type
def non_optional[T](value: T|None)->T:
    assert value is not None
    return value

def f(x: int|None):
    reveal_type(x)
    y = non_optional(x)
    reveal_type(y)

mypy-play

options: list[tuple[int, *tuple[str, ...]]] = [(1, 'a'), (2, 'b', 'c')]
for i, *s in options:
    print(hex(i), '_'.join(s))

mypy-play

for i, s in [(1, ('a',)), (2, ('b', 'c'))]:
    print(hex(i), '_'.join(s))

mypy-play

options: list[tuple[int, *tuple[str, ...]]] = [(1, 'a'), (2, 'b', 'c')]
for i, *s in options:
    print(hex(i), '_'.join(s))

mypy-play

for i, *s in [(1, 'a'), (2, 'b', 'c')]:
    print(hex(i), '_'.join(s))

mypy-play

from typing import Any, cast

i: int
s: tuple[str]

for i, *s in cast(tuple[Any, ...], [(1, 'a'), (2, 'b', 'c')]):
    print(hex(i), '_'.join(s))

mypy-play

from typing import Any, cast

i: int
s: tuple[str]

for i, *s in cast(tuple[Any, ...], [(1, 'a'), (2, 'b', 'c')]):
    print(hex(i), '_'.join(s))

mypy-play

import asyncio
from typing import Awaitable, AsyncGenerator

async def foo(*coros: Awaitable[None]) -> bool:
    gen = (False for f in coros if not await f)
    # Revealed type is "typing.Generator[builtins.bool, None, None]"
    # Runtime type is 'async_generator'
    reveal_type(gen)
    return await anext(gen)

mypy-play

from typing import Any, cast


# A skeleton class based on Django's BaseForm:
# https://github.com/typeddjango/django-stubs/blob/master/django-stubs/forms/forms.pyi
class BaseForm:
    cleaned_data: dict[str, Any] = {}

    def clean(self) -> dict[str, Any] | None:
        return self.cleaned_data

mypy-play

from typing import Any, cast


class BaseForm:
    cleaned_data: dict[str, Any] = {}

    def clean(self) -> dict[str, Any] | None:
        return self.cleaned_data