diff --git a/src/icartt/dataset.py b/src/icartt/dataset.py
index 4d50636e15f9087be9c10a45eb03728acd2cd3c4..ee7c3f43b2f7404cd94b3969d74ef18452d30bad 100644
--- a/src/icartt/dataset.py
+++ b/src/icartt/dataset.py
@@ -200,7 +200,7 @@ class KeywordComment:
         self.data.append(data)
 
     def __str__(self):
-        d = "\n".join(self.data) if not self.data is [] else "N/A" # TODO: use implicit boolean instead of "is []"
+        d = "\n".join(self.data) if self.data else "N/A"
         return self.key + ": " + d