I recommend using python console for experiments. This is much faster than writing the full script. Just enter python + enter and then for example:

(pysteem) 09:27:29 /sandbox$ python
Python 3.4.3 (default, Oct 14 2015, 20:28:29) 
[GCC 4.8.4] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> from steemtools.base import Account
Lost connection to node during wsconnect(): ws://127.0.0.1:8090 (1/-1) Retrying in 0 seconds
Lost connection to node during wsconnect(): ws://127.0.0.1:8090 (1/-1) Retrying in 0 seconds
Lost connection to node during wsconnect(): ws://127.0.0.1:8090 (1/-1) Retrying in 0 seconds
>>> a = Account("cryptomental")
>>> a.get_sp()
227.67634972037933
>>> 
>>> 
>>> a.voting_power()
99.27
>>> quit()
(pysteem) 09:28:49 /sandbox$ 

The warnings that you see in the beginning are 'normal' when you are not using a local node but steem.ws node.