update: fix validators import

djangoldp/tests/models.py

+import validators
 from django.conf import settings
 from django.contrib.auth import get_user_model
 from django.db import models
-from django.utils.datetime_safe import date
 from django.urls import reverse_lazy
-
-import validators
-
+from django.utils.datetime_safe import date
 
 from djangoldp.models import Model
 
@@ -173,6 +171,7 @@ class Circle(Model):
         rdf_type = 'hd:circle'
         depth = 1
 
+
 def webid(self):
     # hack : We user webid as username for external user (since it's an uniq identifier too)
     if validators.url(self.username):
@@ -181,7 +180,8 @@ def webid(self):
         webid = '{0}{1}'.format(settings.BASE_URL, reverse_lazy('user-detail', kwargs={'pk': self.pk}))
     return webid
 
+
 get_user_model()._meta.serializer_fields = ['@id', 'username', 'first_name', 'last_name', 'email', 'userprofile',
                                             'conversation_set', 'circle_set']
 get_user_model().webid = webid
-get_user_model()._meta.anonymous_perms=['view', 'add']
+get_user_model()._meta.anonymous_perms = ['view', 'add']

setup.cfg

@@ -20,6 +20,7 @@ install_requires =
 
 [options.extras_require]
 dev =
+    validators
     factory_boy>=2.11.0
 
 [semantic_release]