Find the last element of a list

Define a function last which returns the last element of a list.

>>> a_list = [0, 1, 2, 3, 4, 5, 6, 7]
>>> last(a_list)
7
>>> another_list = ['a', 'b', 'c', 'd', 'e', 'f']
>>> last(another_list)
'f'

What do you think the return value should be for an empty list?

Solution
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