Need help on RedirectView

Now I am trying Django class based view through Django documentation it going well, but I a problem in RedirectView.

There is `update_counter()` method I don't understand what it is doing and where it come from. I highlight it in the given image.

Please help me

Thanks developers

--
You received this message because you are subscribed to the Google Groups "Django users" group.
To unsubscribe from this group and stop receiving emails from it, send an email to django-users+unsubscribe@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/django-users/CAEoS0z44Zkf2TJNuay6AU1imCdu5ALmuHSzxJxLtgKS_R69wfQ%40mail.gmail.com.