Add a field to distinguish top-level items from others

I think I'll need this for the wikidata completeness filter to only give
results for top-level items, since giving results for their parts would
just duplicate the results needlessly.

rock_paper_sand/media_item.py

@@ -41,6 +41,8 @@ class MediaItem:
         custom_data: Parsed proto.custom_data field, or None.
         done: Parsed proto.done field.
         wikidata_item: Wikidata item, or None.
+        has_parent: Whether or not this item appears in the `parts` field of
+            another item.
         parts: Parsed proto.parts field.
     """
 
@@ -54,6 +56,7 @@ class MediaItem:
     custom_data: Any
     done: multi_level_set.MultiLevelSet
     wikidata_item: wikidata_value.Item | None
+    has_parent: bool
     parts: Sequence["MediaItem"]
 
     @classmethod
@@ -115,6 +118,7 @@ def from_config(
                     if proto.wikidata
                     else None
                 ),
+                has_parent=parent_fully_qualified_name is not None,
                 parts=parts,
             )
 

rock_paper_sand/media_item_test.py

@@ -53,6 +53,7 @@ def test_from_config(self) -> None:
                 custom_data={"a": "b"},
                 done=mock.ANY,
                 wikidata_item=wikidata_value.Item("Q1"),
+                has_parent=False,
                 parts=(
                     media_item.MediaItem(
                         id=mock.ANY,
@@ -64,6 +65,7 @@ def test_from_config(self) -> None:
                         custom_data=None,
                         done=mock.ANY,
                         wikidata_item=None,
+                        has_parent=True,
                         parts=(),
                     ),
                 ),