def get_or_create_manager_with_any_fallback(self) -> TypeInfo | None:
        """
        Create a Manager subclass with fallback to Any for unknown attributes
        and methods. This is used for unresolved managers, where we don't know
        the actual type of the manager.

        The created class is reused if multiple unknown managers are encountered.
        """

        name = "UnknownManager"

        # Check if we've already created a fallback manager class for this
        # module, and if so reuse that.
        manager_info = self.lookup_typeinfo(f"{self.model_classdef.info.module_name}.{name}")
        if manager_info and manager_info.metadata.get("django", {}).get("any_fallback_manager"):
            return manager_info

        fallback_queryset = self.get_or_create_queryset_with_any_fallback()
        if fallback_queryset is None:
            return None
        base_manager_fullname = fullnames.MANAGER_CLASS_FULLNAME
        base_manager_info = self.lookup_typeinfo(base_manager_fullname)
        if base_manager_info is None:
            return None

        base_manager = fill_typevars(base_manager_info)
        assert isinstance(base_manager, Instance)
        manager_info = self.add_new_class_for_current_module(name, [base_manager])
        manager_info.fallback_to_any = True

        manager_info.type_vars = base_manager_info.type_vars
        manager_info.defn.type_vars = base_manager_info.defn.type_vars
        manager_info.metaclass_type = manager_info.calculate_metaclass_type()

        # For methods on BaseManager that return a queryset we need to update
        # the return type to be the actual queryset subclass used. This is done
        # by adding the methods as attributes with type Any to the manager
        # class. The actual type of these methods are resolved in
        # resolve_manager_method.
        for method_name in MANAGER_METHODS_RETURNING_QUERYSET:
            helpers.add_new_sym_for_info(
                manager_info, name=method_name, sym_type=AnyType(TypeOfAny.implementation_artifact)
            )

        manager_info.metadata["django"] = {
            "any_fallback_manager": True,
            "from_queryset_manager": fallback_queryset.fullname,
        }

        return manager_info

        Create a Manager subclass with fallback to Any for unknown attributes
        and methods. This is used for unresolved managers, where we don't know
        the actual type of the manager.

        The created class is reused if multiple unknown managers are encountered.
        
mypy_django_plugin/transformers/models.py