    def make_serverapp(cls, **kwargs):
        """Instantiate the ServerApp

        Override to customize the ServerApp before it loads any configuration
        """
        serverapp = super().make_serverapp(**kwargs)
        if _bool_env("JUPYTERHUB_DISABLE_USER_CONFIG"):
            # disable user-controllable config
            _disable_user_config(serverapp)

        if _bool_env("JUPYTERHUB_SINGLEUSER_TEST_EXTENSION"):
            serverapp.log.warning("Enabling jupyterhub test extension")
            serverapp.jpserver_extensions["jupyterhub.tests.extension"] = True

        return serverapp
Instantiate the ServerApp

Override to customize the ServerApp before it loads any configuration
jupyterhub/singleuser/extension.py