d = dict.fromkeys([1, 2, 3, 4]) l = list(d.keys()) l.sort() print(l) d = dict.fromkeys([1, 2, 3, 4], 42) l = list(d.values()) l.sort() print(l) # argument to fromkeys has no __len__ #d = dict.fromkeys(reversed(range(1))) d = dict.fromkeys((x for x in range(1))) print(d)