Can I somehow reference a Python class that is declared later than the class from which I need to reference without changing their order?

I have these two Python classes(Pydantic schemas which represent SQLAlchemy models):

class Role(RoleBase):
    id: int
    users: list[User] = []

    class Config:
        orm_mode = True

class User(UserBase):
    id: int
    date_created: datetime.datetime
    profile_image: Optional[str] = None

    class Config:
        orm_mode = True

I’ve tried to do it with ForwardRef:

User = ForwardRef('User')
...
users: list[User] = []

or to wrap it with quotes:

users: List['User'] = []

but I get TypeError: issubclass() arg 1 must be a class.

Is there some way to implement this without changing classes’ declaration order?

>Solution :

When using pydantic.ForwardRef, you need to call update_forward_refs on classes that have forward references to update them. So add

Role.update_forward_refs()

after User is defined.

This will all be unnecessary if PEP 649 is accepted.