convert list to tree python code example

Example: convert list to tree python

def normalize(tree, row=0, col=0):
    try:
        node = tree[row][col]
        left  = normalize(tree, row+1, col*2)
        right = normalize(tree, row+1, col*2+1)
        return [node, left, right] if left or right else [node]
    except:
        return None # child index does not exist