diff --git a/python/paddle/utils/plot.py b/python/paddle/utils/plot.py
index 08889c0313fc24151cde6ca7b662d81eb53c9d7b..ee651f2f0cd6f2e594a4e74c896baa924f70bbf5 100644
--- a/python/paddle/utils/plot.py
+++ b/python/paddle/utils/plot.py
@@ -13,6 +13,7 @@
 # limitations under the License.
 
 import os
+import six
 
 
 class PlotData(object):
@@ -60,9 +61,9 @@ class Ploter(object):
 
     def append(self, title, step, value):
         """
-	    Feed data
-	    
-            Args:
+        Feed data
+
+        Args:
                 title: assign the group data to this subtitle.
                 step: the x_axis of data.
                 value: the y_axis of data.
@@ -71,9 +72,9 @@ class Ploter(object):
                 .. code-block:: python
                 plot_curve = Ploter("Curve 1","Curve 2")
                 plot_curve.append(title="Curve 1",step=1,value=1)
-	"""
-        assert isinstance(title, basestring)
-        assert self.__plot_data__.has_key(title)
+        """
+        assert isinstance(title, six.string_types)
+        assert title in self.__plot_data__
         data = self.__plot_data__[title]
         assert isinstance(data, PlotData)
         data.append(step, value)
@@ -89,7 +90,7 @@ class Ploter(object):
                 .. code-block:: python
                 plot_curve = Ploter()
                 plot_cure.plot()
-	"""
+        """
         if self.__plot_is_disabled__():
             return
 
diff --git a/python/paddle/utils/preprocess_img.py b/python/paddle/utils/preprocess_img.py
index a322f7b769a2a32df516a4b8ea04289a7f882ff2..fc67949dfe0ef21487de29678781aa2bfd93f354 100644
--- a/python/paddle/utils/preprocess_img.py
+++ b/python/paddle/utils/preprocess_img.py
@@ -122,7 +122,7 @@ class ImageClassificationDatasetCreater(preprocess_util.DatasetCreater):
     def create_dataset_from_list(self, path):
         data = []
         label_set = []
-        for line in open(file_list):
+        for line in open(path):
             items = line.rstrip.split()
             image_path = items[0]
             label_name = items[1]
@@ -141,7 +141,7 @@ class ImageClassificationDatasetCreater(preprocess_util.DatasetCreater):
         path: the path of the image dataset.
         """
         if self.from_list:
-            return create_dataset_from_list(path)
+            return self.create_dataset_from_list(path)
         label_set = preprocess_util.get_label_set_from_dir(path)
         data = []
         for l_name in list(label_set.keys()):