def guest_reset(self, userid):
        """reset a virtual machine
        :param str userid: the id of the virtual machine to be reset
        :returns: None
        """
        action = "reset guest '%s'" % userid
        with zvmutils.log_and_reraise_sdkbase_error(action):
            self._vmops.guest_reset(userid)
reset a virtual machine
        :param str userid: the id of the virtual machine to be reset
        :returns: None