I want to share some class level attributes among different declarative base classes in SQLAlchemy, such as type_annotation_map.

I tried the next:

from sqlalchemy import JSON
from sqlalchemy.orm import declared_attr, DeclarativeBase


class BaseMixin:
    @declared_attr
    def type_annotation_map(cls):
        return {
            list: JSON,
            dict: JSON
        }


class Base1(BaseMixin, DeclarativeBase):
    pass


class Base2(BaseMixin, DeclarativeBase):
    pass

Unfortunately, resulted in sqlalchemy.exc.ArgumentError when trying to map Python list type to corresponding SQLAlchemy Core type.