This issue raised too much bikeshedding. To wrap it up, I'll modify the patch with the following: - processes renamed to workers - `workers` defaults to 1 - When `workers` is equal to 0, then `os.cpu_count` will be used - When `workers` > 1, multiple processes will be used - When `workers` == 1, run normally (no multiple processes) - Negative values really should raise a ValueError (as multiprocessing.Pool and soon concurrent.futures.Thread/ProcessPoolExecutor) - Will raise NotImplementedError if multiprocessing can't be used (when `workers` equals to 0 or > 1) If anyone agrees with the above, then I'll modify the patch. This will be its last iteration, any other bikeshedding should be addressed by the core dev who'll apply it. Thank you.