diff --git a/python/paddle/trainer/PyDataProvider2.py b/python/paddle/trainer/PyDataProvider2.py
index dfa7496cf5aa5410739c525ecb9258b2eb85cbab..0f0b0a1175336f202e8ac5a6ed1c35aff250a6e2 100644
--- a/python/paddle/trainer/PyDataProvider2.py
+++ b/python/paddle/trainer/PyDataProvider2.py
@@ -200,24 +200,26 @@ class CheckWrapper(object):
         for each in item:
             callback(each)
 
+
 class CheckInputTypeWrapper(object):
     def __init__(self, generator, input_types, logger):
         self.generator = generator
         self.input_types = input_types
         self.logger = logger
 
-    def __call__(self, obj, filename): 
-       for items in self.generator(obj, filename):
-           try:
-               # dict type is required for input_types when item is dict type 
-               assert (isinstance(items, dict) and \
-                       not isinstance(self.input_types, dict))==False
-               yield items
-           except AssertionError as e:
-               self.logger.error(
+    def __call__(self, obj, filename):
+        for items in self.generator(obj, filename):
+            try:
+                # dict type is required for input_types when item is dict type 
+                assert (isinstance(items, dict) and \
+                        not isinstance(self.input_types, dict))==False
+                yield items
+            except AssertionError as e:
+                self.logger.error(
                     "%s type is required for input type but got %s" %
                     (repr(type(items)), repr(type(self.input_types))))
-               raise
+                raise
+
 
 def provider(input_types=None,
              should_shuffle=None,
@@ -372,8 +374,8 @@ def provider(input_types=None,
                     self.generator = InputOrderWrapper(self.generator,
                                                        self.input_order)
                 else:
-                    self.generator = CheckInputTypeWrapper(self.generator, self.slots,
-                                                           self.logger) 
+                    self.generator = CheckInputTypeWrapper(
+                        self.generator, self.slots, self.logger)
                 if self.check:
                     self.generator = CheckWrapper(self.generator, self.slots,
                                                   check_fail_continue,