How to type a Complex Enum in .pyi file?

[attack68]

Defining a complex enum e.g:

#[pyclass(eq)]
#[derive(Debug, Clone, PartialEq)]
pub enum MyEnum {
    A { val: u32 },
    B { name: String },
}

can be typed in the stub file as:

class MyEnum:
    @classmethod
    def A(cls, val: int) -> MyEnum: ...
    @classmethod
    def B(cls, name: str) -> MyEnum: ...

Although when using Python isinstance checks like

isinstance(obj, MyEnum.A):  # test works but mypy complains incompatible type.
    obj.val  #  <-- mypy error since val is not a declared attribute

Complex Enums are very useful objects in PyO3 but I struggle with these properties and pickling them which is another issue. Anyone with any ideas?

[Icxolu]

Complex enums are build using a class hierarchy. Each variant will be it's own class inheriting from a common base class for all variants. The base class has attributes for each variant class. Something like the following:

class MyEnum:
    A: MyEnumA
    B: MyEnumB

class MyEnumA(MyEnum):
    val: int

class MyEnumB(MyEnum):
    name: str

I think this can also be written like this, which reads a little nicer.

class MyEnum:
    class A(MyEnum):
        val: int
    
    class B(MyEnum):
        name: str

[attack68]

Thanks I needed to extend this to:

class MyEnum:
    class A(MyEnum):
        val: int
        def __init__(self, val: int) -> None: ...
    
    class B(MyEnum):
        name: str
        def __init__(self, name: str) -> None: ...

But this did indeed solve many mypy errors.