Fixes:
Lambda Function
>>> arr_list = [[1, 4], [3, 3], [5, 7]]
>>> sorted_list = sorted(arr_list, key=lambda x: x[1])
>>> sorted_list
[[3, 3], [1, 4], [5, 7]]
Sliding windows
>>> from itertools import islice
>>> def slide(list_name, window_size):
... z = [islice(list_name, i, None) for i in range(window_size)]
... return zip(*z)