FIX: Get rid of basestring (not python3 compatible).

dav_events/converters.py

@@ -1,6 +1,7 @@
 import datetime
 import logging
 import re
+from six import string_types
 
 logger = logging.getLogger(__name__)
 
@@ -53,7 +54,7 @@ class Iso8601Serializer(object):
     @classmethod
     def deserialize(cls, value, ignore_unsupported_input=False):
         prefix = '{marker}{sep}'.format(marker=cls.marker, sep=cls.separator)
-        if isinstance(value, basestring) and value.startswith(prefix):
+        if isinstance(value, string_types) and value.startswith(prefix):
             haystack = value[len(prefix):]
             m = cls._re.match(haystack)
             if m is not None:
@@ -68,6 +69,6 @@ class Iso8601Serializer(object):
             elif not ignore_unsupported_input:
                 raise ValueError('Format not recognized \'{str}\''.format(str=haystack))
         elif not ignore_unsupported_input:
-            raise ValueError('Expected basestring,'
+            raise ValueError('Expected string type,'
                              ' not {}'.format(value.__class__.__name__))
         return value

dav_events/forms/events.py

@@ -9,6 +9,7 @@ from django.apps import apps
 from django.utils.translation import get_language, ugettext, ugettext_lazy as _
 from django_countries.fields import Country, LazyTypedChoiceField
 from datetimewidget.widgets import DateWidget, TimeWidget, DateTimeWidget
+from six import string_types
 
 from .. import choices
 from .. import config
@@ -162,7 +163,7 @@ class EventCreateForm(ModelMixin, ChainedForm):
         kwargs = self._session_data.copy()
         if 'deadline' in kwargs:
             buf = kwargs['deadline']
-            if isinstance(buf, basestring):
+            if isinstance(buf, string_types):
                 deadline_choice = buf.lower()
                 deadline_field = 'deadline_{}'.format(deadline_choice)
                 if deadline_field in kwargs: