diff --git a/qurator/dinglehopper/edit_distance.py b/qurator/dinglehopper/edit_distance.py
index dc1cb24..a6643c7 100644
--- a/qurator/dinglehopper/edit_distance.py
+++ b/qurator/dinglehopper/edit_distance.py
@@ -123,7 +123,11 @@ def seq_editops(seq1, seq2):
 
 
 def editops(word1, word2):
-    # XXX Note that this returns indices to the _grapheme clusters_, not characters!
+    """
+    Return sequence of edit operations transforming one string to another.
+
+    Note that this returns indices to the _grapheme clusters_, not characters!
+    """
     word1 = list(grapheme_clusters(unicodedata.normalize('NFC', word1)))
     word2 = list(grapheme_clusters(unicodedata.normalize('NFC', word2)))
     return seq_editops(word1, word2)