Python & binary tree help PLEASE?!?????????please please please help me in anyway :'(?

Write a Python program that :

a: Takes in as input a list of numbers (Note that you have to type in these numbers using the

keyboard)

using:

def insert(tree, key):

if len(tree) == 0:

return [key, [], []]

else:

if key < tree[0]:

return [tree[0], insert(tree[1], key), tree[2]]

else:

return [tree[0], tree[1], insert(tree[2], key)]

def construct(ls, tree):

if len(ls) == 0:

return tree

else:

return construct(ls[1:], insert(tree,ls[0]))

def main(ls):

if len(ls) == 0:

return []

else:

t = construct(ls, tree)

print t

ls = []

#Write code to enter your letters here one by one and add each one of them to the list ls

tree = []

main(ls)

c: Add a function called total() that takes in as input this list and and finds the sum of all the nodes in

the constructed binary tree.

d: Return as output, the total value of all the nodes in the binary tree.

i have no idea what to add by " #Write code to enter your letters here one by one and add each one of them to the list ls", please anyone help?? :( even steps or ANY help at all please:((((