diff --git a/kws/bin/plot_det_curve.py b/kws/bin/plot_det_curve.py
index 231a9e1..64feebb 100644
--- a/kws/bin/plot_det_curve.py
+++ b/kws/bin/plot_det_curve.py
@@ -1,5 +1,5 @@
 # Copyright (c) 2021 Binbin Zhang(binbzha@qq.com)
-#                    Menglong Xu 
+#                    Menglong Xu
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -36,18 +36,19 @@ def plot_det_curve(keywords, stats_dir, figure_file):
     plt.rcParams['ytick.direction'] = 'in'
     plt.rcParams['text.usetex'] = True
     plt.rcParams['font.size'] = 12
-    
+
     for index, keyword in enumerate(keywords):
-        stats_file = os.path.join(stats_dir, 'stats.'+str(index)+'.txt')
+        stats_file = os.path.join(stats_dir, 'stats.' + str(index) + '.txt')
         values = load_stats_file(stats_file)
         plt.plot(values[:, 0], values[:, 1], label=keyword)
 
     plt.xlim([0, 5])
     plt.ylim([0, 0.35])
-    plt.xticks([0, 1, 2, 3, 4, 5], ['0', '1','2','3','4','5'])
-    plt.yticks([0, 0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35], ['0', '5','10','15','20','25','30','35'])
+    plt.xticks([0, 1, 2, 3, 4, 5], ['0', '1', '2', '3', '4', '5'])
+    plt.yticks([0, 0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35],
+        ['0', '5', '10', '15', '20', '25', '30', '35'])
     plt.xlabel('False Alarm Per Hour')
-    plt.ylabel('False Rejection Rate (\%)')
+    plt.ylabel('False Rejection Rate (\\%)')
     plt.grid(linestyle='--')
     plt.legend(loc='best', fontsize=16)
     plt.savefig(figure_file)
@@ -55,10 +56,11 @@ def plot_det_curve(keywords, stats_dir, figure_file):
 
 if __name__ == '__main__':
     parser = argparse.ArgumentParser(description='plot det curve')
-    parser.add_argument('--keywords', required=True, help='keywords, must in the same order as in "dict/words.txt" separated by ", "')
+    parser.add_argument('--keywords', required=True, 
+        help='keywords, must in the same order as in "dict/words.txt" separated by ", "')
     parser.add_argument('--stats_dir', required=True, help='dir of stats files')
     parser.add_argument('--figure_file', required=True, help='path to save det curve')
-    
+
     args = parser.parse_args()
 
     keywords = args.keywords.strip().split(', ')