Django 2.0 removes the
django.core.urlresolvers module, which was moved to
django.urls in version 1.10. You should change any import to use django.urls instead, like this:
from django.urls import reverse
Note that Django 2.0 removes some features that previously were in
django.core.urlresolvers, so you might have to make some more changes before your code works. See the features deprecated in 1.9 for details on those additional changes.