def get_os_id(uname_func=None):
 uname_func = (uname_func or os.uname)
 (sysname, _, release, _, machine) = uname_func()
 os_id = _ID_BY_OS.get(sysname.lower())
 if os_id:
  return os_id(release, machine)
 return None

def get_os_id ( uname_func = None ) : uname_func = ( uname_func or os . uname ) ( sysname , _ , release , _ , machine ) = uname_func ( ) os_id = _ID_BY_OS . get ( sysname . lower ( ) ) if os_id : return os_id ( release , machine ) return None
return an os identifier sensitive only to its major version .