diff --git a/models/rank/dien/reader.py b/models/rank/dien/reader.py
index 16ff27a6d82adf7e5fd703bcb79cb8e06798540a..b79838c8fb1014c17319738cac0361ebc536c8b5 100755
--- a/models/rank/dien/reader.py
+++ b/models/rank/dien/reader.py
@@ -102,10 +102,10 @@ class Reader(ReaderBase):
             else:
                 len_seq = len(b[i][0])
                 start_idx = random.randint(0, self.max_neg_item - len_seq - 1)
-                self.neg_candidate_item[start_idx:start_idx + len_seq +
-                                        1] = b[i][0]
-                self.neg_candidate_cat[start_idx:start_idx + len_seq +
-                                       1] = b[i][1]
+                self.neg_candidate_item[start_idx:start_idx + len_seq +1] = b[
+                    i][0]
+                self.neg_candidate_cat[start_idx:start_idx + len_seq +1] = b[
+                    i][1]
 
             for _ in range(len(b[i][0])):
                 randindex = random.randint(0, len(self.neg_candidate_item) - 1)