By default, (with a minimal vimrc, and no plugins installed), this is already possible.
Vim ships with multiple filetype plugins and some of these plugins offer omni-completion right out of the box. For example, python comes with pythoncomplete.vim.
If you use the default pythoncomplete.vim that ships with Vim, (i.e. no YouCompleteMe, no python-mode, no jedi-vim), you get a preview window when you complete a function, that shows the keyword arguments.
All you need is Vim with
+python feature (
:echo has('python') shows 1). If you do, then this is all it takes to enable the default python omni-completion with your vimrc:
filetype plugin indent on
After hunting down many other completion solutions for python (jedi, python-mode), I've come to like pythoncomplete.vim that is shipped with Vim a lot more. It's simple, and most important to me, it's very stable, especially compared to solutions like jedi-vim/python-mode and YouCompleteMe.
This is what the default solution looks like. It doesn't offer completion of arguments, but just shows them in the preview window so it's easy for you to fill the keyword arguments in like so: