1>>> dictionary = { 1: 'one', 2:'two', 3:'three' }
2>>> dictionary['ONE'] = dictionary.pop(1)
3>>> dictionary
4{2: 'two', 3: 'three', 'ONE': 'one'}
5>>> dictionary['ONE'] = dictionary.pop(1)
6Traceback (most recent call last):
7 File "<input>", line 1, in <module>
8KeyError: 1