mypy-play

from typing import Concatenate, Callable

def foo[**P](fn: Callable[P, None], x: int, *args: P.args, **kwargs: P.kwargs) -> None: ...

def test(a: str) -> None: ...

foo(fn=test, x=1, a="")

mypy-play

from typing import Self, reveal_type

class NodeA:
    def __init__(self: Self) -> None:
        reveal_type(self)  # Self`0
        self.myself: Self = self  # ✅️

class NodeB:
    def __init__(self) -> None:
        reveal_type(self)  # __main__.NodeB

mypy-play

from typing import Protocol, Self

class FloatScalar[FloatT](Protocol):
    def pow(self, arg: FloatT) -> Self: ...

def upcast(arg: FloatScalar[object]) -> FloatScalar[float]:
    return arg  # ✅️

mypy-play

from typing import Protocol, Self

class FloatScalar[FloatT](Protocol):
    def pow(self, arg: FloatT) -> Self: ...

def upcast(arg: FloatScalar[object]) -> FloatScalar[float]:
    return arg  # ✅️

mypy-play

from typing import Protocol, Self

class FloatScalar[FloatT](Protocol):
    def pow(self, arg: FloatT) -> Self | complex: ...

def upcast(arg: FloatScalar[object]) -> FloatScalar[float]:
    return arg

mypy-play

from typing import reveal_type
from typing import Generator, AsyncGenerator

def async_returns_generator() -> Generator[int, int, None] | AsyncGenerator[int, int]:
    x = yield 1
    reveal_type(x)
    return None

mypy-play

from typing import Protocol, TypedDict, Unpack, Any


class Factory(Protocol):
    def __call__(self, **kwargs: Any) -> Any:
        pass


def use_factory(factory: Factory):
    pass

mypy-play

from typing import Protocol, TypedDict, Unpack, Any


class Factory(Protocol):
    def __call__(self, **kwargs: Any) -> Any:
        pass


def use_factory(factory: Factory):
    pass

mypy-play

from unittest.mock import Mock


class O: ...


def take_o(o: O) -> None: ...


take_o(Mock())

mypy-play

from typing import Iterable, Protocol
from dataclasses import dataclass


@dataclass
class Square:
    sidelength: float

    def area(self) -> float:
        return self.sidelength * self.sidelength