We don't have following weird stuff implemented:

>>> a = [1,2,3,4]
>>> a[1:3] = [10,11,12,13]
>>> a
[1, 10, 11, 12, 13, 4]
>>> del a[2:5]
>>> a
[1, 10, 4]

This first of all relevant for lists, but should watch out for other types too.