Merge branch 'development'

AUTHORS

@@ -1,3 +1,4 @@
+Bertrand Svetchine https://github.com/bsvetchine
 Elena Williams <elena.williams@thecut.net.au>
 Matt Austin <matt.austin@thecut.net.au>
-Josh Crompton <josh.crompton@thecut.net.au>
+Josh Crompton <josh.crompton@thecut.net.au>

thecut/durationfield/models.py

@@ -5,6 +5,7 @@
 from django.db import models
 from django.utils.translation import ugettext_lazy as _
 from django.core.exceptions import ValidationError
+from django.utils.six import with_metaclass
 from isodate.isoerror import ISO8601Error
 import isodate
 
@@ -15,15 +16,13 @@
     add_introspection_rules = None
 
 
-class ISO8601DurationField(models.Field):
+class ISO8601DurationField(with_metaclass(models.SubfieldBase, models.Field)):
     """Store and retrieve ISO 8601 formatted durations.
 
     """
 
     description = _("A duration of time (ISO 8601 format)")
 
-    __metaclass__ = models.SubfieldBase
-
     default_error_messages = {
         'invalid': _("This value must be in ISO 8601 Duration format."),
         'unknown_type': _("The value's type could not be converted"),