@idiokit.stream
    def lookup(self, asn):
        try:
            asn = int(asn)
        except __HOLE__:
            idiokit.stop(())

        results = self._cache.get(asn, None)
        if results is not None:
            idiokit.stop(results)

        try:
            txt_results = yield dns.txt(
                "AS{0}.asn.cymru.com".format(asn),
                resolver=self._resolver)
        except dns.DNSError:
            idiokit.stop(())

        results = _split(txt_results, self._keys)
        self._cache.set(asn, results)
        idiokit.stop(results)
dataset/ETHPy150Open abusesa/abusehelper/abusehelper/core/cymruwhois.py/ASNameLookup.lookup