title: Python tarfile module overwrites existing files during extraction - how to disable it?
body: <p>Is there a way prevent <code>tarfile.extractall</code> (<a href="http://docs.python.org/library/tarfile.html#tarfile.TarFile.extractall" rel="nofollow">API</a>) from overwriting existing files? By "prevent" I mean ideally raising an exception when an overwrite is about to happen. The current behavior is to silently overwrite the files.</p>