diff --git a/egs/librispeech/ASR/pruned_transducer_stateless7/train.py b/egs/librispeech/ASR/pruned_transducer_stateless7/train.py
index 258457f98..1030be528 100755
--- a/egs/librispeech/ASR/pruned_transducer_stateless7/train.py
+++ b/egs/librispeech/ASR/pruned_transducer_stateless7/train.py
@@ -845,9 +845,9 @@ def train_one_epoch(
             if cur_grad_scale < 1.0 or (cur_grad_scale < 8.0 and batch_idx % 400 == 0):
                 scaler.update(cur_grad_scale * 2.0)
             if cur_grad_scale < 0.01:
-                logging.warn("Grad scale is small: {cur_grad_scale}")
+                logging.warning(f"Grad scale is small: {cur_grad_scale}")
             if cur_grad_scale < 1.0e-05:
-                raise RuntimeError("grad_scale is too small, exiting: {cur_grad_scale}")
+                raise RuntimeError(f"grad_scale is too small, exiting: {cur_grad_scale}")
 
         if batch_idx % params.log_interval == 0:
             cur_lr = scheduler.get_last_lr()[0]