diff --git a/egs/librispeech/WSASR/local/prepare_otc_lang.py b/egs/librispeech/WSASR/local/prepare_otc_lang.py
index 2b71438c6..01865b865 100755
--- a/egs/librispeech/WSASR/local/prepare_otc_lang.py
+++ b/egs/librispeech/WSASR/local/prepare_otc_lang.py
@@ -35,8 +35,8 @@ consisting of words and tokens (i.e., phones) and does the following:
 5. Generate L_disambig.pt, in k2 format.
 """
 import argparse
-import math
 import logging
+import math
 import re
 from collections import defaultdict
 from pathlib import Path
diff --git a/icefall/otc_phone_graph_compiler.py b/icefall/otc_phone_graph_compiler.py
index 4f22cde44..bebdffe0c 100644
--- a/icefall/otc_phone_graph_compiler.py
+++ b/icefall/otc_phone_graph_compiler.py
@@ -22,8 +22,8 @@ from typing import List, Union
 import k2
 import torch
 
-from icefall.utils import str2bool
 from icefall.lexicon import Lexicon
+from icefall.utils import str2bool
 
 
 class OtcPhoneTrainingGraphCompiler(object):