Add get_descendings

src/documents/managers.py

@@ -22,6 +22,15 @@ class DocumentManager(models.Manager):
         """Get all child documents for a specific document ID."""
         return self.filter(dc_child__id=id).order_by('dc_child__ordering')
 
+    def get_descendings(self, *ids):
+        """Get all parent documents for some document IDs."""
+        from documents.models import DocumentChildren
+        dcs = DocumentChildren.objects.filter(id__in=ids).order_by('id', 'ordering').only('id', 'child').select_related('child')
+        return {
+            pk: [dc.child for dc in items]
+            for pk, items in groupby(dcs, lambda d: d.id)
+        }
+
     def get_related(self, id):
         """Get all parent and child documents for a specific document ID."""
         return self.filter(