def test_resolves13RootServers(self):
        """
        The L{IResolverSimple} supplied to L{root.bootstrap} is used to lookup
        the IP addresses of the 13 root name servers.
        """
        stubResolver = StubResolver()
        root.bootstrap(stubResolver)
        self.assertEqual(
            stubResolver.calls,
            [((s,), {}) for s in ROOT_SERVERS])

        The L{IResolverSimple} supplied to L{root.bootstrap} is used to lookup
        the IP addresses of the 13 root name servers.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/names/test/test_rootresolve.py