def get_group_dns(self):
if self._group_dns is None:<EOL><INDENT>group_infos = self._get_group_infos()<EOL>self._group_dns = set(group_info[<NUM_LIT:0>] for group_info in group_infos)<EOL><DEDENT>return self._group_dns<EOL>
Returns a (cached) set of the distinguished names in self._group_infos.