def _ra_pid_for(dev):
 pid_file = _ra_file(dev, 'pid')
 if os.path.exists(pid_file):
  with open(pid_file, 'r') as f:
   return int(f.read())

def _ra_pid_for ( dev ) : pid_file = _ra_file ( dev , 'pid' ) if os . path . exists ( pid_file ) : with open ( pid_file , 'r' ) as f : return int ( f . read ( ) )
returns the pid for prior radvd instance for a bridge/device .