Proposed command when using cpu could be changed

[Constantin Lehenmeier]

First of all, thank you very much for your project!

I encountered a problem when using a cpu and executing the proposed command:
python test.py --data_path_test=./your/test/data/path/ --parallel None --schema test --batch_size 1

If you use parallel None the arg parameter parallel will not be None; you can leave the parameter because the default value is already None: python test.py --data_path_test=./your/test/data/path/ --schema test --batch_size 1

Best regards
Constantin