mypy-play

from typing import Iterator


def fib(n: int) -> Iterator[int]:
    a, b = 0, 1
    while a < n:
        yield a
        a, b = b, a + b

mypy-play

import os
from pathlib import Path
def foo() -> list[str| Path]:
    return ["a", "b", Path("/tmp")]

def main() -> None:

    cmd_line = foo() 
    file = cmd_line[0]
    args = cmd_line[1:]

mypy-play

import os
from pathlib import Path
def foo() -> list[str|os.PathLike[str]]:
    return ["a", "b", Path("/tmp")]

def main() -> None:

    cmd_line = foo() 
    file = cmd_line[0]
    args = cmd_line[1:]

mypy-play

from typing import TypeVar, Generic

T = TypeVar("T")

class W(Generic[T]):
   def managed(self) -> T:
       raise NotImplementedError

class MW(Generic[T]):
    def __init__(self, w: T) -> None:

mypy-play

from typing import Generic, TypeVar

T = TypeVar("T")


class Foo(Exception, Generic[T]): ...


try:
    raise Foo

mypy-play

from enum import Enum
from typing import Self

class E(Enum):
    def __new__(cls, arg: int) -> Self: ...

    A = "a", "b"  # Type error, too many arguments.

mypy-play

def test() -> dict[str, int]:
    vals = {'hi': 3, 'ho': 4}
    return vals

mypy-play

from collections.abc import Sequence
from enum import Enum
from typing import Self, overload

class MyStr(Sequence["MyStr"]):
    @overload
    def __new__(cls, object: object = ...) -> Self: ...
    @overload
    def __new__(cls, object: bytes, encoding: str = ..., errors: str = ...) -> Self: ...

mypy-play

from enum import Enum

class StrEnum(str, Enum):
    A = "a"  # ok
    B = b"b", "utf-8"  # ok, see the typeshed definition of `str.__new__`
    C = "too", "many", "arguments", "provided"  # runtime error: TypeError: str() takes at most 3 arguments (4 given)

mypy-play

from enum import Enum

class MyStrEnum(str, Enum):
    A = "a"  # ok
    B = b"b", "utf-8"  # ok, see the typeshed definition of `str.__new__`
    C = "too", "many", "arguments", "provided"  # runtime error: TypeError: str() takes at most 3 arguments (4 given)