220         return key in self._map

   220         return key in self._map

   221 

   221 

   222     def __iter__(self):

   222     def __iter__(self):

   223         for x in sorted(self._map):

   223         for x in sorted(self._map):

   224             yield x

   224             yield x

   225 

   228 

   226     def parents(self):

   229     def parents(self):

   227         return [self._validate(p) for p in self._pl]

   230         return [self._validate(p) for p in self._pl]

   228 

   231 

   229     def p1(self):

   232     def p1(self):