diff --git a/python/paddle/v2/dataset/conll05.py b/python/paddle/v2/dataset/conll05.py
index cf1ea8ac5a3f14d79c71bceafd61a43ca7919111..2638b63989cc4af5981280dc91c9b0c34735acb2 100644
--- a/python/paddle/v2/dataset/conll05.py
+++ b/python/paddle/v2/dataset/conll05.py
@@ -24,7 +24,6 @@ import gzip
 import itertools
 from common import download
 
-
 __all__ = ['test, get_dict', 'get_embedding']
 
 DATA_URL = 'http://www.cs.upc.edu/~srlconll/conll05st-tests.tar.gz'
diff --git a/python/paddle/v2/dataset/movielens.py b/python/paddle/v2/dataset/movielens.py
index 822f7f293df126434c9aee89fc13b87ccf0c342f..ea0f83b8d405eda6a4c55f849235367149e7da20 100644
--- a/python/paddle/v2/dataset/movielens.py
+++ b/python/paddle/v2/dataset/movielens.py
@@ -42,6 +42,7 @@ class MovieInfo(object):
     """
     Movie id, title and categories information are stored in MovieInfo.
     """
+
     def __init__(self, index, categories, title):
         self.index = int(index)
         self.categories = categories
@@ -68,6 +69,7 @@ class UserInfo(object):
     """
     User id, gender, age, and job information are stored in UserInfo.
     """
+
     def __init__(self, index, gender, age, job_id):
         self.index = int(index)
         self.is_male = gender == 'M'
diff --git a/python/paddle/v2/inference.py b/python/paddle/v2/inference.py
index 848546a1df420f83774fad367561ca0c2628fb78..a39b46b40f10093fcff7c8de13de61807ac7f168 100644
--- a/python/paddle/v2/inference.py
+++ b/python/paddle/v2/inference.py
@@ -19,6 +19,7 @@ class Inference(object):
     :param parameters: The parameters dictionary.
     :type parameters: paddle.v2.parameters.Parameters
     """
+
     def __init__(self, output_layer, parameters):
         topo = topology.Topology(output_layer)
         gm = api.GradientMachine.createFromConfigProto(
diff --git a/python/paddle/v2/trainer.py b/python/paddle/v2/trainer.py
index 15fcefef45b3a8a4e70ddbf1d94aeb2652c7f5bd..4a6d912596da472059dc5c5a673017a66d9b71b4 100644
--- a/python/paddle/v2/trainer.py
+++ b/python/paddle/v2/trainer.py
@@ -14,7 +14,6 @@ from . import parameters as v2_parameters
 __all__ = ['SGD']
 
 
-
 def default_event_handler(event):
     """
     Default event handler. It will print some log and save mode.