code: def get_paths_cfg(
      sys_file='pythran.cfg',
      platform_file='pythran-{}.cfg'.format(sys.platform),
      user_file='.pythranrc'
  ):
      
      sys_config_dir = os.path.dirname(__file__)
      sys_config_path = os.path.join(sys_config_dir, sys_file)
  
      platform_config_path = os.path.join(sys_config_dir, platform_file)
  
      user_config_path = os.environ.get('PYTHRANRC', None)
      if not user_config_path:
          user_config_dir = os.environ.get('XDG_CONFIG_HOME', '~')
          user_config_path = os.path.expanduser(
              os.path.join(user_config_dir, user_file))
      return {"sys": sys_config_path, "platform": platform_config_path, "user": user_config_path}
docs: >>> os.environ['HOME'] = '/tmp/test'
      >>> get_paths_cfg()['user']
      '/tmp/test/.pythranrc'
      >>> os.environ['HOME'] = '/tmp/test'
      >>> os.environ['XDG_CONFIG_HOME'] = '/tmp/test2'
      >>> get_paths_cfg()['user']
      '/tmp/test2/.pythranrc'
      >>> os.environ['HOME'] = '/tmp/test'
      >>> os.environ['XDG_CONFIG_HOME'] = '/tmp/test2'
      >>> os.environ['PYTHRANRC'] = '/tmp/test3/pythranrc'
      >>> get_paths_cfg()['user']
      '/tmp/test3/pythranrc'