@classmethod<EOL><INDENT>def get_pid_from_request(cls, changelist, request):<DEDENT>
val = request.GET.get(cls.PARENT_ID_QS_PARAM, False)<EOL>pid = val or None<EOL>try:<EOL><INDENT>del changelist.params[cls.PARENT_ID_QS_PARAM]<EOL><DEDENT>except KeyError:<EOL><INDENT>pass<EOL><DEDENT>return pid<EOL>
Gets parent ID from query string.

        :param changelist:
        :param request:
        :return: