diff --git a/python/ray/data/dataset.py b/python/ray/data/dataset.py
index efdb7556d47e..179f5769acc4 100644
--- a/python/ray/data/dataset.py
+++ b/python/ray/data/dataset.py
@@ -671,7 +671,7 @@ def process_next_batch(batch: DataBatch) -> Iterator[Block]:
             if output_buffer.has_next():
                 yield output_buffer.next()
 
-        # breakpoint()
+        # TODO(chengsu): pass function name to MapBatches logical operator.
         if hasattr(fn, "__self__") and isinstance(
             fn.__self__, ray.data.preprocessor.Preprocessor
         ):