Merge pull request #4715 from voxel51/bug/delegated-output

Delegated outputs may be None

fiftyone/operators/delegated.py

@@ -405,7 +405,8 @@ async def _execute_operator(self, doc):
             outputs = await resolve_type_with_context(
                 request_params, "outputs"
             )
-            outputs_schema = outputs.to_json()
+            if outputs is not None:
+                outputs_schema = outputs.to_json()
         except (AttributeError, Exception):
             logger.warning(
                 "Failed to resolve output schema for the operation."