Add `db.Model` typing workaround in docs?

[TitaniumHocker]

mypy currently does not correctly handle inheritance from a class attribute with a model - db.Model:

error: Name "db.Model" is not defined  [name-defined]

According on the related bugreport, this issue will not be resolved anytime soon.

So, there is working workaround:

import typing as t
from flask_sqlalchemy import SQLAlchemy
from flask_sqlalchemy.model import Model as BaseModel

db = SQLAlchemy()

if t.TYPE_CHECKING:
    class Model(BaseModel):
        pass
else:
    Model = db.Model

class MyModel(Model):
    pass

It will be useful if this workaround will be mentioned in documentation.
I can make changes to the documentation myself if I get the approval.

[davidism]

I don't plan to add MyPy workarounds to the docs at this time. Also, this isn't correct from a typing perspective, the class used during type checking is not a SQLAlchemy declarative base. I'd suggest adding an ignore rule for the name-defined error in model files to your mypy config.

I suggest anyone having an issue with this add their vote to the linked issue python/mypy#8603.

[TitaniumHocker]

Also, this isn't correct from a typing perspective, the class used during type checking is not a SQLAlchemy declarative base.

If it's incorrect - pls provide valid example.

Maybe something like?:

class Model(DeclarativeMeta, BaseModel):