$6.$ This is a coding exercise that Google has used in interviews with a modification $...$

Write a function findSum that takes as its arguments:

$-$ a sorted list of positive integers lst$,$ and

$-$ an integer sum.

findSum searches for two elements lst$[$i$]$ and lst$[$j$]$ such that lst$[$i$]+$lst$[$j$]==$ sum and i $\backslash (!=$j $\backslash ).$ If such a pair of elements exists, the function returns the tuple $(\backslash ($ i$,$ j $\backslash ))$; otherwise it returns None.

So$,$ for example,

findSum$([1,2,3,9],8)$ is None

while

findSum$([1,2,4,4],8)$ is $(2,3)$

Do this using recursion. Write code to test your function. $[2\mathrm{.}75$ hour challenge$]$