fix python errors

newsbox/models.py

@@ -242,10 +242,11 @@ class NewsboxBase(six.with_metaclass(NewsboxModelBase, models.Model)):
         if not self.newsbox_published:
             self.newsbox_published = True
             updated = True
-        now_datetime = now()
-        if now_datetime < self.newsbox_publication_start_date:
-            self.newsbox_publication_start_date = now_datetime
-            updated = True
+        if self.newsbox_publication_start_date:
+            now_datetime = now()
+            if now_datetime < self.newsbox_publication_start_date:
+                self.newsbox_publication_start_date = now_datetime
+                updated = True
         if updated and commit:
             self.save()
         return updated
@@ -306,10 +307,10 @@ class NewsboxExpiredBase(six.with_metaclass(NewsboxModelBase, models.Model)):
 
     def publish(self, commit=True):
         updated = super(NewsboxExpiredBase, self).publish(commit=False)
-        now_datetime = now()
-        if now_datetime > self.newsbox_publication_end_date:
-            self.newsbox_publication_end_date = None
-            updated = True
+        if self.newsbox_publication_end_date:
+            if now() > self.newsbox_publication_end_date:
+                self.newsbox_publication_end_date = None
+                updated = True
         if updated and commit:
             self.save()
         return updated

newsbox_cms/admin.py

@@ -63,7 +63,7 @@ def CustomModelCMSAdminFactory(
             """
             output = ''
             edit_url = reverse(
-                'admin:%s_%s_change' % (obj._meta.app_label, obj._meta.module_name),
+                'admin:%s_%s_change' % (obj._meta.app_label, obj._meta.model_name),
                 args=[obj.pk])
 
             show_url = None