def __dir__ ( self ) : return sorted ( self . keys ( ) | { m for m in dir ( self . __class__ ) if m . startswith ( 'to_' ) } )
python all methods object show
u Returns a list of children and available helper methods .
def __dir__(self):
        u"""Returns a list of children and available helper methods."""
        return sorted(self.keys() | {m for m in dir(self.__class__) if m.startswith('to_')})