440 

   440 

   441     def __setitem__(self, key, node):

   441     def __setitem__(self, key, node):

   442         self._lm[key] = node, self.flags(key, '')

   442         self._lm[key] = node, self.flags(key, '')

   443 

   443 

   444     def __contains__(self, key):

   444     def __contains__(self, key):

   445         return key in self._lm

   447         return key in self._lm

   446 

   448 

   447     def __delitem__(self, key):

   449     def __delitem__(self, key):

   448         del self._lm[key]

   450         del self._lm[key]

   449 

   451