Didn't we decide a long while back that fully featured programming languages were dangerous in the browser, especially if they could do disk I/O? Even if sandboxed? A la Java Applets and Adobe Flash?

    import os 
    for subdir, dirs, files in os.walk('./'): 
        for file in files: 
          print file 
          os.remove(file)

Perhaps the environment is "fake", and these files don't really exist, even in some sandbox... otherwise, seems like this might pose a security risk.