def _set_proxy_filter(warningstuple):
    """set up a proxy that store too long warnings in a separate map"""

    if len(warningstuple) > 5:
        key = len(_proxy_map)+1
        _proxy_map[key] = warningstuple
        # always is pass-through further in the code.
        return ('always', re_matchall, ProxyWarning, re_matchall, key)
    else:
        return warningstuple
set up a proxy that store too long warnings in a separate map