trainAsync is not a function

I get this error when trying to use 'net.trainAsync'

```js
TypeError: net.trainAsync is not a function
at train (/home/container/index.js:21:13)
```

Code:
```js
const pool = workerpool.pool();

await net.trainAsync(data, {
iterations: 2000,
errorThresh: 0.01,
log: true,
logPeriod: 100,
useWorkers: true,
learningRate: 0.01,
callbackPeriod: 10,
callback: function(stats) {

if (stats.accuracy > 0.9) {
pool.terminate();
console.log('Training finished');
client.user.setPresence({
status: 'online',
activities: [{ name: 'Estou pronta para uso!', type: 'WATCHING' }]
});
}
}
});