diff --git a/egs/wenetspeech/ASR/transducer_stateless/model.py b/egs/wenetspeech/ASR/transducer_stateless/model.py
index c324b57bf..46050e5ab 100644
--- a/egs/wenetspeech/ASR/transducer_stateless/model.py
+++ b/egs/wenetspeech/ASR/transducer_stateless/model.py
@@ -106,11 +106,14 @@ class Transducer(nn.Module):
 
         max_sym_id = torch.max(y_padded)
         assert encoder_out.size(0) == decoder_out.size(0), [
-            encoder_out.size(), decoder_out.size()]
+            encoder_out.size(),
+            decoder_out.size()]
         assert encoder_out.size(2) == decoder_out.size(2), [
-            encoder_out.size(), decoder_out.size()]
+            encoder_out.size(),
+            decoder_out.size()]
         assert encoder_out.size(2) >= (max_sym_id + 1), [
-            encoder_out.size(), max_sym_id]
+            encoder_out.size(),
+            max_sym_id]
 
         boundary = torch.zeros(
             (x.size(0), 4), dtype=torch.int64, device=x.device