determining appropriate platform-specific directories (PyPy)

 Depending on your system (Linux, Mac OS X, or Windows), you have to use
 different directories for storing user data. appdirs will help you choose an
 appropriate:
 .
  * user data directory (user_data_dir function)
  * user config directory (user_config_dir function)
  * user cache directory (user_cache_dir function)
  * site data directory (site_data_dir function)
  * site config directory (site_config_dir function)
  * user log directory (user_log_dir function)
 .
 On Linux systems, these function return directories based on the XDG Base
 Directory Specification.
 .
 This is the PyPy version of the package.