I am trying to use YouTubeinMp3's API to write a script which will download the music file on sending a request to a particular endpoint.

```
import requests
import json

si = {'video': 'https://www.youtube.com/watch?v=zTgLhIjiSas', 'autostart': 1}
res = requests.get("https://www.youtubeinmp3.com/download/", params = si)
print len(res.content)

```

Now, the resulting URL ie `https://www.youtubeinmp3.com/download/?video=https://www.youtube.com/watch?v=zTgLhIjiSas&autostart=1` automatically starts downloading the corresponding mp3 file of the given video. 

However, on executing the above script, the file does not start downloading. The `status_code` returned is `200`. What seems to be wrong with my code?