    def _orm_server_changed(self, change):
        """When we get an orm_server, get attributes from there."""
        obj = change.new
        self.proto = obj.proto
        self.ip = obj.ip
        self.port = obj.port
        self.base_url = obj.base_url
        self.cookie_name = obj.cookie_name
When we get an orm_server, get attributes from there.
jupyterhub/objects.py