linters

apps/activity/models.py

@@ -201,8 +201,8 @@ class Entry(models.Model):
     def save(self, *args, **kwargs):
         qs = Entry.objects.filter(~Q(pk=self.pk), activity=self.activity, note=self.note, guest=self.guest)
         if qs.exists():
-            raise ValidationError(_("Already entered on ") +
+            raise ValidationError(_("Already entered on ")
-                                  _("{:%Y-%m-%d %H:%M:%S}").format(timezone.localtime(qs.get().time), ))
+                                  + _("{:%Y-%m-%d %H:%M:%S}").format(timezone.localtime(qs.get().time), ))
 
         if self.guest:
             self.note = self.guest.inviter