How to parse a base64-encoded cookies into their normal representation?

Given a base64-encoded cookie, how do I parse it into a sequence of human-readable pairs? For example:

gAN9cQBYDgAAAC5pbnN0YWdyYW0uY29tcQF9cQJYAQAAAC9xA31xBChYCQAAAGNzcmZ0b2tlbnEF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\nT25seXE/TnN1YnVzcy4=

If I split it by '\n' and then decode with b64decode I get readable cookie names but not the values.