def bootstrap(resolver):
    domains = [chr(ord('a') + i) for i in range(13)]
    # f = lambda r: (log.msg('Root server address: ' + str(r)), r)[1]
    f = lambda r: r
    L = [resolver.getHostByName('%s.root-servers.net' % d).addCallback(f) for d in domains]
    d = defer.DeferredList(L)
    d.addCallback(lambda r: Resolver([e[1] for e in r if e[0]]))
    return DeferredResolver(d)
Lookup the root nameserver addresses using the given resolver
dataset/ETHPy150Open kuri65536/python-for-android/python-modules/twisted/twisted/names/root.py/bootstrap