How directly send to room

in errbot guide

![Imgur](https://i.imgur.com/5UtvdzS.png)

```python
        self.send(
            self.build_identifier("code_runtime_alert"),
            "test"
        )

```

the `code_runtime_alert` is my stream room name

but i view the source code `build_identifier` only return a `ZulipPerson` class

can you give me some example or docs? Thanks