def basis(self, region=None): # this assumes a _basis_walker method in the subquotient object wk = self._sq._basis_walker(region) if self._am.graded_basis(region).cardinality() < Infinity: cat = FiniteEnumeratedSets() else: cat = InfiniteEnumeratedSets() res = Family(wk, lambda i: i, lazy=True) res._refine_category_(cat) return res