diff --git a/icefall/utils.py b/icefall/utils.py
index bc262ec28..b85b6bf7b 100644
--- a/icefall/utils.py
+++ b/icefall/utils.py
@@ -472,16 +472,13 @@ class LossRecord(collections.defaultdict):
         all processes get the total.
         """
         keys = sorted(self.keys())
-        s = torch.tensor([ float(self[k]) for k in keys ],
+        s = torch.tensor([float(self[k]) for k in keys],
                          device=device)
         dist.all_reduce(s, op=dist.ReduceOp.SUM)
         for k, v in zip(keys, s.cpu().tolist()):
             self[k] = v
 
-    def write_summary(self, 
-                      tb_writer: SummaryWriter, 
-                      prefix: str, 
-                      batch_idx: int) -> None:
+    def write_summary(self, tb_writer: SummaryWriter, prefix: str, batch_idx: int) -> None:
         """Add logging information to a TensorBoard writer.
         
         Args: