2354         for x in self._subset:

  2354         for x in self._subset:

  2355             if cond(x):

  2355             if cond(x):

  2356                 yield x

  2356                 yield x

  2357 

  2357 

  2358     def __and__(self, x):

  2358     def __and__(self, x):

  2360 

  2360 

  2361     def __sub__(self, x):

  2361     def __sub__(self, x):

  2362         return lazyset(self, lambda r: r not in x)

  2362         return lazyset(self, lambda r: r not in x)

  2363 

  2363 

  2364     def __add__(self, x):

  2364     def __add__(self, x):