Is building the merkle tree working?

Hi i'am trying to understand und use the merkle tree for change detection but it looks like it's not working:

```js
const tsmp1 = new Timestamp(1643977312925, 0, "clientId")
const tsmp2 = new Timestamp(1643977311825, 0, "clientId")

const timestamps = [tsmp1,tsmp2];

const tree = merkle.build(timestamps);
```

tree ist empty. I'am doing something wrong?