basestring to six.string_types for Python 3

awx/api/renderers.py

@@ -5,6 +5,8 @@
 from rest_framework import renderers
 from rest_framework.request import override_method
 
+import six
+
 
 class BrowsableAPIRenderer(renderers.BrowsableAPIRenderer):
     '''
@@ -69,7 +71,7 @@ class PlainTextRenderer(renderers.BaseRenderer):
     format = 'txt'
 
     def render(self, data, media_type=None, renderer_context=None):
-        if not isinstance(data, basestring):
+        if not isinstance(data, six.string_types):
             data = unicode(data)
         return data.encode(self.charset)