from typing import TYPE_CHECKING from catalog.common import Item, ItemCategory class Collection(Item): if TYPE_CHECKING: from journal.models import Collection as JournalCollection journal_item: "JournalCollection" category = ItemCategory.Collection @property def url(self): return self.journal_item.url if hasattr(self, "journal_item") else super().url @property def owner_id(self): return self.journal_item.owner_id if self.journal_item else None