':return: the xml description for the given roleset.'

def roleset(self, roleset_id):

    baseform = roleset_id.split(u'.')[0]
    baseform = baseform.replace(u'perc-sign', u'%')
    baseform = baseform.replace(u'oneslashonezero', u'1/10').replace(u'1/10', u'1-slash-10')
    framefile = (u'frames/%s.xml' % baseform)
    if (framefile not in self._framefiles):
        raise ValueError((u'Frameset    file    for    %s    not    found' % roleset_id))
    etree = ElementTree.parse(self.abspath(framefile).open()).getroot()
    for roleset in etree.findall(u'predicate/roleset'):
        if (roleset.attrib[u'id'] == roleset_id):
            return roleset
    else:
        raise ValueError((u'Roleset    %s    not    found    in    %s' % (roleset_id, framefile)))
