This had better not work...

node-is-a-liar-snippet-2.js

var net = require('net');

function startServer(port, host, callback) {
    var server = net.createServer();
    server.listen(port, host, function() {
        callback(undefined, server);
    });
    server.on('error', function(error) {
        console.error('Ah damn!', error);
        callback(error);
    });
}

startServer(4000, '0.0.0.0', function(error, wildcardServer) {
    if (error) return;
    startServer(4000, '127.0.0.1', function(error, localhostServer) {
        if (error) return;
        console.log('Started both servers!');
    });
});

When I run this exact code on my computer, I get this error:

Ah damn! Error: listen EADDRINUSE: address already in use 127.0.0.1:4000
    at Server.setupListenHandle [as _listen2] (node:net:1319:16)
    at listenInCluster (node:net:1367:12)
    at doListen (node:net:1505:7)
    at processTicksAndRejections (node:internal/process/task_queues:84:21) {
  code: 'EADDRINUSE',
  errno: -98,
  syscall: 'listen',
  address: '127.0.0.1',
  port: 4000
}

I cannot make them to run and print "Started both servers!"