'Run an SSH command and assert no output returned.'

def run_ssh_assert_no_output(self, ssh_cmd):

    (out, err) = self._run_ssh(ssh_cmd)
    if (len(out.strip()) != 0):
        msg = (_('Expected    no    output    from    CLI    command    %(cmd)s,    got    %(out)s.') % {'cmd': '    '.join(ssh_cmd), 'out': out})
        LOG.error(msg)
        raise exception.VolumeBackendAPIException(data=msg)
