I am sorry. I have not actually spend time to get familiar with the code. But I got the error with the previous `render` function.
```vim

Error detected while processing function Powerline:
line    3:
2013-04-11 14:30:53,212:ERROR:vim:rvm_current:Exception while computing segment: render() takes exactly 1 argument (4 given)
Error detected while processing function Powerline:
line    3:
Traceback (most recent call last):
Error detected while processing function Powerline:
line    3:
  File "/Library/Python/2.7/site-packages/Powerline-beta-py2.7.egg/powerline/theme.py", line 91, in get_segments
Error detected while processing function Powerline:
line    3:
    contents = segment['contents_func'](pl=self.pl, **segment['args'])
Error detected while processing function Powerline:
line    3:
  File "/Library/Python/2.7/site-packages/Powerline-beta-py2.7.egg/powerline/lib/threaded.py", line 67, in __call__
Error detected while processing function Powerline:
line    3:
    return self.render(update_value, update_first=update_first, pl=pl, **kwargs)
Error detected while processing function Powerline:
line    3:
TypeError: render() takes exactly 1 argument (4 given)   
```