HTTPError: 400 Client Error: Bad Request for url: https://app.firebaseio.com/essential/activepassive.json

I've been using python-firebase to push data since a long time but today, I'm facing this issue:
HTTPError: 400 Client Error: Bad Request for url: https://app.com/essential/activepassive.json
Code:
```
from firebase import firebase 
firebase=firebase.FirebaseApplication('https://app.firebaseio.com/',None)
firebase.put('/essential','activepassive',dictionary)

```