make abstract return a dict

objaverse_xl/abstract.py

@@ -1,5 +1,5 @@
 from abc import ABC, abstractmethod
-from typing import Callable, Optional
+from typing import Callable, Optional, Dict
 
 import pandas as pd
 
@@ -30,7 +30,7 @@ class ObjaverseSource(ABC):
         handle_modified_object: Optional[Callable] = None,
         handle_missing_object: Optional[Callable] = None,
         **kwargs
-    ) -> None:
+    ) -> Dict[str, str]:
         """Downloads all objects from the source.
 
         Args:
@@ -87,6 +87,7 @@ class ObjaverseSource(ABC):
                 Return is not used. Defaults to None.
 
         Returns:
-            None
+            Dict[str, str]: Mapping of file identifiers to local paths of the downloaded
+                3D objects.
         """
         pass