如何在 python 中定义 final classvar 变量

Question

As you can see in PEP 526 we can define static variable class with ClassVar word. like below

class Starship:
    stats: ClassVar[dict[str, int]] = {} # class variable
    damage: int = 10                     # instance variable

And another typing feature as you can see in PEP 591 we can define constant (readonly) variable with Final word, like below

class Connection:
    TIMEOUT: Final[int] = 10

My question is how to combine these two words to say my class static variable is Final?

for example is below code is valid?

class Connection:
    TIMEOUT: Final[ClassVar[int]] = 10

Answer 1

From PEP-591 :

Type checkers should infer a final attribute that is initialized in a class body as being a class variable. Variables should not be annotated with both ClassVar and Final.

So you ca just use:

class Connection:
    TIMEOUT: Final[int] = 10