There're tons of apps/widgets for PHP function reference and even for Ruby but I'm shocked to find there is nothing available for a popular language like Python (besides the official online documentation ofcourse). 
Is there really not a single handy reference widget/app available for Python? I have 'Pocket Reference' book, but a dashboard widget would be so handy!
The interactive interpreter is a fantastic reference tool. dir(<identifier) lists all the attributes of a module, class, or function help(<identifier>) gives you help about same.
pydoc at the command line is another great tool. It does for Python what man gives you for commands, plus it even includes a web server you can start up to see the documentation in your browser.
Python Function Reference