def host_power_action(self, host, action):
        """The only valid values for 'action' on XenServer are 'reboot' or
        'shutdown', even though the API also accepts 'startup'. As this is
        not technically possible on XenServer, since the host is the same
        physical machine as the hypervisor, if this is requested, we need to
        raise an exception.
        """
        if ("reboot", "shutdown") in action:
            return self._vmops.host_power_action(host, action)
        else:
            msg = _("Host startup on XenServer is not supported.")
            raise NotImplementedError(msg)
dataset/ETHPy150Open nii-cloud/dodai-compute/nova/virt/xenapi_conn.py/XenAPIConnection.host_power_action/swapped operands of `in`