You extend the class based view by using inheritance:
class MyRegistrationView(RegistrationView):
def __init__(self, *args, **kwargs):
k = 1 + 1
super(MyRegistrationView, self).__init__(*args, **kwargs)
then define custom route:
url(r'^registration/register/$', MyRegistrationView.as_view(),
name='registration_register'),
url('^registration/', include('registration.urls')),
the order is important! Our custom route need to be defined before registration app routes.