django2.2: fix urls and adapt them to new format

pedagogy/views.py

@@ -33,7 +33,7 @@ from django.views.generic import (
 from django.utils import html
 from django.http import HttpResponse
 from django.core.exceptions import PermissionDenied, ObjectDoesNotExist
-from django.core.urlresolvers import reverse_lazy, reverse
+from django.urls import reverse_lazy, reverse
 from django.shortcuts import get_object_or_404
 from django.conf import settings