- Don't allow strings to be sent as arguments. The mixup with
lists/tuples could be dangerous.
- Don't escape arguments. subprocess.Popen takes care that arguments
are passed on nicely to the actions.
- Update tests.
The package license (AGPL3+) implicitly indicates the license of each
file. However, it is desirable to have license headers in each file.
This is the case for many prominent projects like GNU project, Mozilla
etc.