1# test passing a user-defined mapping as the argument to ** 2 3def foo(**kw): 4 print(sorted(kw.items())) 5 6class Mapping: 7 def keys(self): 8 # the long string checks the case of string interning 9 return ['a', 'b', 'c', 'abcdefghijklmnopqrst'] 10 11 def __getitem__(self, key): 12 if key == 'a': 13 return 1 14 else: 15 return 2 16 17foo(**Mapping()) 18