python code

Recall that we defined a leaf labelled tree by saying $"$an LLT is either a int, or a list$[$LLT$]",$ and that we wrote this in Python as:

LLT $=$ int $|$ list$[\text{'}$LLT$\text{'}]$

$```$

Write a function llt$\_$max$\_$value. It takes an LLT and a callable function that consumes a

single integer and returns the leaf in the tree that gives the greatest value when evaluated at

the callable function. In the case of a tie return the left most value when drawn.

$```$

For example,

def digit$\_$sum$($n: int$)->$ int:

$"""$Returns the sum of digits of n$"""$

n $=$ abs$($n$)$

s $=0$

while n $>0$:

s $+=$ n $\%10$

n $=$ n $//10$

return s

check.expect$("$T$1",$ digit$\_$sum$(0),0)$

check.expect$("$T$2",$ digit$\_$sum$(1234567890),45)$

check.expect$("$LLT digit sum",

llt$\_$max$\_$value$([[[31],[45,7]],[[[[88],[311,[96]]],[10,6]]]],$

digit$\_$sum$),88)$

check.expect$("$LLT digit sum ties",

llt$\_$max$\_$value$([[[31],[4,13]],[[[[1111],[112,[211]]],[121,22]]]],$

digit$\_$sum$),31)$