diff --git a/backend/data_import/pipeline/label.py b/backend/data_import/pipeline/label.py
index adc5bfeeae..82efa2a1f1 100644
--- a/backend/data_import/pipeline/label.py
+++ b/backend/data_import/pipeline/label.py
@@ -26,7 +26,7 @@ def __init__(self, **data):
 
     @abc.abstractmethod
     def __lt__(self, other):
-        raise NotImplementedError()
+        return NotImplemented
 
     @classmethod
     def parse(cls, example_uuid: UUID4, obj: Any):