Sorting of a list, which consists of 2-lists, by sorting them according to the second list element.
>>> lst=[[2,6],[1,3],[5,4],[1,0]]
>>> lst.sort(key=lambda x: x[1])
>>> lst
[[1, 0], [1, 3], [5, 4], [2, 6]]
Sort according to the sum of the components of a 2-tuple:
>>> lst=[[2,6],[1,3],[5,4],[1,0]]
>>> lst.sort(key = sum)
>>> print(lst)
[[1, 0], [1, 3], [2, 6], [5, 4]]
>>>