+ @staticmethod
+ def as_id_list(items: list[dict[str, object]]) -> list[int | str]:
+ """Return list of only 'id' fields of items."""
+ id_list = []
+ for item in items:
+ assert isinstance(item['id'], (int, str))
+ id_list += [item['id']]
+ return id_list
+
+ @staticmethod
+ def as_refs(items: list[dict[str, object]]
+ ) -> dict[str, dict[str, object]]:
+ """Return dictionary of items by their 'id' fields."""
+ refs = {}
+ for item in items:
+ refs[str(item['id'])] = item
+ return refs
+