diff --git a/cornac/data/dataset.py b/cornac/data/dataset.py
index b5fea86c8..fa9846863 100644
--- a/cornac/data/dataset.py
+++ b/cornac/data/dataset.py
@@ -699,7 +699,7 @@ def chrono_user_basket_data(self):
 
         if self.__chrono_user_basket_data is None:
             self.__chrono_user_basket_data = defaultdict()
-            for (bid, ids), t in zip(*self.baskets.values(), self.basket_timestamps):
+            for (bid, ids), t in zip(self.baskets.items(), self.basket_timestamps):
                 u = self.uir_tuple[0][ids[0]]
                 u_data = self.__chrono_user_basket_data.setdefault(u, ([], []))
                 u_data[0].append(bid)