How to solve binary tree Branch sum problem : Coding Interview Question

Don't click this: https://bit.ly/3cmuoAn Write a function that takes in a binary tree and returns a list of its branch sums (ordered from the sum of the left branch to the sum of the branch at right). A branch sum is the sum of all values within a branch of the Binary Tree. A branch of a Binary Tree is a path in a tree that begins at the root node and ends at any leaf node.