diff --git a/markdownx/forms.py b/markdownx/forms.py
index 6a7fc5b..4cd60a3 100755
--- a/markdownx/forms.py
+++ b/markdownx/forms.py
@@ -1,9 +1,10 @@
 import os
 import uuid
-import StringIO
+
 
 from django import forms
 from django.conf import settings
+from django.utils.six import StringIO
 from django.utils.translation import ugettext_lazy as _
 from django.core.files.uploadedfile import InMemoryUploadedFile
 from django.template import defaultfilters as filters
diff --git a/markdownx/widgets.py b/markdownx/widgets.py
index 27115e9..907f953 100755
--- a/markdownx/widgets.py
+++ b/markdownx/widgets.py
@@ -9,7 +9,7 @@ from .settings import MARKDOWNX_EDITOR_RESIZABLE
 class MarkdownxWidget(forms.Textarea):
 
     def render(self, name, value, attrs=None):
-        if attrs.has_key('class'):
+        if 'class' in attrs.keys():
             attrs['class'] += ' markdownx-editor'
         else:
             attrs.update({'class':'markdownx-editor'})
diff --git a/setup.py b/setup.py
index 5f5e3fc..e6f8910 100755
--- a/setup.py
+++ b/setup.py
@@ -24,6 +24,7 @@ setup(
         'Topic :: Software Development :: User Interfaces',
         'Operating System :: OS Independent',
         'Programming Language :: Python :: 2.7',
+        'Programming Language :: Python :: 3.5',
         'Programming Language :: JavaScript',
     ],
     keywords='django markdown live preview images upload',