fix relative path

models/ticket.py

@@ -3,7 +3,7 @@ from django.db import models, transaction
 from django.urls import reverse
 
 from tickets.models.ticket_list import TicketList
-from tickets.lib.tickets import Ticket as T
+from ..lib.tickets import Ticket as T
 
 class Ticket(models.Model):
     TICKET_TYPES = T.TICKET_TYPES