'Eat a domain-list command and return error, empty, or results.'

def _parse_domain_list(self, *cmd):

    if self._fail_domain_list:
        raise processutils.ProcessExecutionError(exit_code=1)
    elif self._empty_domain_list:
        return ('', '')
    else:
        return ('thisserver\nthatserver\nanotherserver\n', '')
