def uuid(dev=None):
 try:
  if (dev is None):
   return list(os.walk('/sys/fs/bcache/'))[0][1][0]
  else:
   return os.path.basename(_bcsys(dev, 'cache'))
 except:
  return False

def uuid ( dev = None ) : try : if ( dev is None ) : return list ( os . walk ( '/sys/fs/bcache/' ) ) [ 0 ] [ 1 ] [ 0 ] else : return os . path . basename ( _bcsys ( dev , 'cache' ) ) except : return False
generate unique id in uuid4 format .