Checks if the instance is up and running.

        :param str instance_id: instance identifier

        :return: bool - True if running, False otherwise

def is_instance_running(self, instance_id):
        """Checks if the instance is up and running.

        :param str instance_id: instance identifier

        :return: bool - True if running, False otherwise
        """

        # Here, it's always better if we update the instance.
        instance = self._load_instance(instance_id, force_reload=True)
        return instance.status == 'ACTIVE'