'Move issues in ``issue_keys`` to the backlog, removing them from all sprints that have not been completed.
:param issue_keys: the issues to move to the backlog'

def move_to_backlog(self, issue_keys):

    if (self._options[u'agile_rest_path'] == GreenHopperResource.AGILE_BASE_REST_PATH):
        url = self._get_url(u'backlog/issue', base=self.AGILE_BASE_URL)
        payload = {u'issues': issue_keys}
        try:
            self._session.post(url, data=json.dumps(payload))
        except JIRAError as e:
            if (e.status_code == 404):
                warnings.warn(u'Status    code    404    may    mean,    that    too    old    JIRA    Agile    version    is    installed.    At    least    version    6.7.10    is    required.')
            raise
    else:
        raise NotImplementedError((u'No    API    for    moving    issues    to    backlog    for    agile_rest_path="%s"' % self._options[u'agile_rest_path']))
