diff --git a/RIAssigner/data/SimpleData.py b/RIAssigner/data/SimpleData.py
index f56dcfb..11240e5 100644
--- a/RIAssigner/data/SimpleData.py
+++ b/RIAssigner/data/SimpleData.py
@@ -1,5 +1,5 @@
 from copy import copy
-from typing import Iterable
+from typing import Iterable, Optional
 
 from RIAssigner.utils import is_sorted
 
@@ -51,3 +51,6 @@ def retention_times(self) -> Iterable[Data.RetentionTimeType]:
     def retention_indices(self, values: Iterable[Data.RetentionIndexType]):
         raise NotImplementedError()
 
+    @property
+    def comment(self) -> Iterable[Optional[str]]:
+        return None
\ No newline at end of file