code: def auth_complete(self, *args, **kwargs):
          
          if SESSION_VAR not in self.strategy.request.session:
              # This is the only protection layer when people
              # go directly to the passthrough login view.
              logger.warn("Auth data for passthrough provider not found in session. Raising 404.")
              raise PermissionDenied
          auth_data = self.strategy.request.session[SESSION_VAR]
          kwargs.update({'response': auth_data, 'backend': self})
          return self.strategy.authenticate(*args, **kwargs)
docs: Completes loging process, must return user instance