Use python to clean up cached pytest and executable files

python -Bc "import pathlib; [p.unlink() for p in pathlib.Path('.').rglob('*.py[co]')]"
python -Bc "import pathlib; [p.rmdir() for p in pathlib.Path('.').rglob('__pycache__')]"
python -Bc "import pathlib; import shutil; [shutil.rmtree(p) for p in pathlib.Path('.').rglob('.pytest_cache')]"