diff --git a/TODO b/TODO
index 68430440c903be88cb6a6ad21de9d2ac9a97d116..d6845d8cf363a57d6a5da40b72f303bcde14cfc1 100644
--- a/TODO
+++ b/TODO
@@ -70,3 +70,4 @@ Division of 0 by 1 reduces to 0.
    >>> @
    2 / 7 + 4 / 11
 
+ - filter_duplicates does not seem to work anymore...