Capturing Screenshot and saving to a Document with Python background script

I’m doing some testing activity which requires me to capture screenshot of applications/DB etc and save it to a document. The whole activity has more than 50 screenshots. Is there a way in Python through which I can take a screenshot with windows shortcut key( eg; CTRL ALT shift C) and it appends the image to a document file. I believe the python program should be running in background like nohup in Unix Can some one please guide me.