def get_pk_instance(self, model: TypeInfo, /) -> Instance:
        """
        Get a primary key instance of provided model's type info. If primary key can't be resolved,
        return a default declaration.
        """
        contains_from_pk_info = model.get_containing_type_info("pk")
        if contains_from_pk_info is not None:
            pk = contains_from_pk_info.names["pk"].node
            if isinstance(pk, Var):
                pk_type = get_proper_type(pk.type)
                if isinstance(pk_type, Instance):
                    return pk_type
        return self.default_pk_instance

        Get a primary key instance of provided model's type info. If primary key can't be resolved,
        return a default declaration.
        
mypy_django_plugin/transformers/models.py