Telegram first run doesn't work, Invalid backend

Installed 2.5.1 as:
```
%> sudo -H pip install 'ntfy[telegram,emoji]'
```

Trying to run as per docs:
```
%> ntfy -b telegram send "hello world"
ERROR: Invalid backend telegram
```
My .config/ntfy/ntfy.yml is very simple, removing it does not help nor does adding telegram to the backends list or adding an empty telegram config block:
```
backends:
- pushover
pushover:
user_key: FOO
```

Installed on Ubuntu LTS 16.04, python2.7
```
%> python -V
Python 2.7.12
```