You might (either for this or some other project) look into JSON as a lightweight persistence format (
www.json.org). Your data looks a lot like a dictionary, and JSON will do that fine. There's a parser module in the Python stdlib since 2.6.
I offer this as a tip from another Pythonista, not to try to influence you to change your mind on your current format. I've liked JSON when I wanted something more than key-value but less than XML.