la solucion es usar copy, te pongo aqui un ejemlpo:
>>> import copy
>>> listOne = [{"name": "Willie", "city": "Providence, RI"}, 1, "tomato", 3.0]
>>> listTwo = listOne[:] # or listTwo=copy.copy(listOne)
>>> listThree = copy.deepcopy(listOne)
>>> listOne.append("kid")
>>> listOne[0]["city"] = "San Francisco, CA"
>>> print listOne, listTwo, listThree
[{'name': 'Willie', 'city': 'San Francisco, CA'}, 1, 'tomato', 3.0, 'kid']
[{'name': 'Willie', 'city': 'San Francisco, CA'}, 1, 'tomato', 3.0]
[{'name': 'Willie', 'city': 'Providence, RI'}, 1, 'tomato', 3.0]
Para más informacion : http://oreilly.com/catalog/lpython/chapter/ch09.html