>>> from contest import change

>>> names = ['Pau', 'Anna', 'Pol', 'Joan', 'Maria']
>>> change (names, 'Pol', 2, 'Maria', 4)
>>> names
['Pau', 'Anna', 'Maria', 'Joan', 'Pol']

>>> names = ['Pau', 'Anna', 'Pol', 'Joan', 'Maria']
>>> change (names, 'Pol', 2, 'Pau', 0)
>>> names
['Pol', 'Anna', 'Pau', 'Joan', 'Maria']

>>> names = ['Pau', 'Anna', 'Pol', 'Joan', 'Maria']
>>> change (names, 'Anna', 1, 'Pau', 0)
>>> names
['Anna', 'Pau', 'Pol', 'Joan', 'Maria']