diff --git a/demo/quick_start/api_predict.py b/demo/quick_start/api_predict.py
index 9c224e3cdbab692cb18221aa193cbb9b699a3117..a1a9ef7bca3301f260a0ad899e46ec1b4a81b052 100755
--- a/demo/quick_start/api_predict.py
+++ b/demo/quick_start/api_predict.py
@@ -18,13 +18,12 @@ from optparse import OptionParser
 from py_paddle import swig_paddle, DataProviderConverter
 from paddle.trainer.PyDataProvider2 import sparse_binary_vector
 from paddle.trainer.config_parser import parse_config
-
-
 """
 Usage: run following command to show help message.
   python api_predict.py -h
 """
 
+
 class QuickStartPrediction():
     def __init__(self, train_conf, dict_file, model_dir=None, label_file=None):
         """
@@ -72,9 +71,7 @@ class QuickStartPrediction():
         transform word into integer index according to the dictionary.
         """
         words = data.strip().split()
-        word_slot = [
-            self.word_dict[w] for w in words if w in self.word_dict
-        ]
+        word_slot = [self.word_dict[w] for w in words if w in self.word_dict]
         return word_slot
 
     def batch_predict(self, data_batch):
@@ -84,6 +81,7 @@ class QuickStartPrediction():
         print("predicting labels is:")
         print prob
 
+
 def option_parser():
     usage = "python predict.py -n config -w model_dir -d dictionary -i input_file "
     parser = OptionParser(usage="usage: %s [options]" % usage)
@@ -144,5 +142,6 @@ def main():
     print labels
     predict.batch_predict(batch)
 
+
 if __name__ == '__main__':
     main()