| 844 | |
| 845 | |
| 846 | class KeysView(MappingView, Set): |
| 847 | |
| 848 | __slots__ = () |
| 849 | |
| 850 | @classmethod |
| 851 | def _from_iterable(cls, it): |
| 852 | return set(it) |
| 853 | |
| 854 | def __contains__(self, key): |
| 855 | return key in self._mapping |
| 856 | |
| 857 | def __iter__(self): |
| 858 | yield from self._mapping |
| 859 | |
| 860 | |
| 861 | KeysView.register(dict_keys) |
no outgoing calls