A list that spans infinitely in both directions
Values can be set and retrieved using functions, subscripts, or slices.
Using slices with steps other step values e.g. li[0:10:2] is not implemented yet.
from infinite_list import InfiniteList
li = InfiniteList()
li[0] = 'a'
li[1:4] = 'b', 'c', 'd'
li[-7] = 'z'
li[2:] = 'w'
li[:5] = 'q'