From what I can tell all this does is move the pickling process to the multiprocessing module, so it 'fixes the problem' by moving the call to pickle into the standard library (so automated code auditing tools or the dude complaining about the usage won't find it) and just removes some (useful) error handling in the process, as well as repeating the pickling process twice. It's entirely an effort to shut up the complaining and doesn't meaningfully change the security of the system at all (which was already fine).