fails to parse subscribers on edge

Using r175 of lp:~bughelper-dev/python-launchpad-bugs/main, parsing a bug's subscriber list fails as follows:

Traceback (most recent call last):
  File "/home/lp_archive/bin/sru-accept", line 34, in <module>
    bug.subscribers.add('ubuntu-sru')
  File "/home/lp_archive/python/launchpadbugs/lphelper.py", line 256, in <lambda>
    if fget : fget = lambda s, n=fget.__name__ : getattr(s, n)()
  File "/home/lp_archive/python/launchpadbugs/html_bug.py", line 81, in func
    x.parse()
  File "/home/lp_archive/python/launchpadbugs/html_bug.py", line 1033, in parse
    parse_error(False, "Subscribers.__xml.edge.stable", xml=self.__xml, url=self.__url)
  File "/home/lp_archive/python/launchpadbugs/exceptions.py", line 220, in parse_error
    raise PythonLaunchpadBugsXMLParsingError(path, xml, url)
launchpadbugs.exceptions.PythonLaunchpadBugsXMLParsingError: Wrong XPath-Expr while parsing Subscribers.__xml.edge.stable (https://bugs.edge.launchpad.net/ubuntu/+source/hal-info/+bug/295251)

Here's the serialised XML that it's trying to parse. Looks like python-launchpad-bugs doesn't know about the content-link stuff?

<div class="portlet" id="portlet-subscribers">
  <div class="section">
    <div><a style="
      background: url(/@@/edit) center left no-repeat;
      line-height: 20px;
      padding-left: 18px" href="https://bugs.edge.launchpad.net/ubuntu/+source/hal-info/+bug/295251/+subscribe" class="menu-link-subscription">Subscribe/Unsubscribe</a></div>
    <div><a style="
      background: url(/@@/add) center left no-repeat;
      line-height: 20px;
      padding-left: 18px" href="https://bugs.edge.launchpad.net/ubuntu/+source/hal-info/+bug/295251/+addsubscriber" class="menu-link-addsubscriber">Subscribe someone else</a></div>
  </div>
  <a id="subscribers-content-link" href="/bugs/295251/+bug-portlet-subscribers-content"></a>
  <div id="subscribers-portlet-spinner" style="text-align: center; display: none">
    <img src="/@@/spinner"></div>
  <script type="text/javascript">
    YUI().use('io-base', 'node', function(Y) {
      Y.on('domready', function() {
        Y.get('#subscribers-portlet-spinner').setStyle('display', 'block');

        function hide_spinner() {
          Y.get('#subscribers-portlet-spinner').setStyle('display', 'none');
        }

        function on_success(transactionid, response, arguments) {
          hide_spinner();
          var portlet = Y.get('#portlet-subscribers');
          portlet.set('innerHTML',
                      portlet.get('innerHTML') + response.responseText);
        }

        var config = {on: {success: on_success,
                           failure: hide_spinner}};
        var url = Y.get('#subscribers-content-link').getAttribute('href').replace('bugs.', '');
        Y.io(url, config);
      });
    });
  </script></div>