docs: def merge_accounts(self, request):
          """
          Attach NetID account to regular django
          account and then redirect user. In this situation
          user dont have to fill extra fields because he filled
          them when first account (request.user) was created.
  
          Note that self.indentity must be already set in this stage by
          validate_response function.
          """
          # create new net ID record in database
          # and attach it to request.user account.
          try:
              netid = NetID.objects.get(identity=self.identity, provider=self.provider)
          except NetID.DoesNotExist:
              netid = NetID(user=request.user, identity=self.identity, provider=self.provider)
              netid.save()
              # show nice message to user.
              messages.add_message(request, messages.SUCCESS, lang.ACCOUNTS_MERGED)