import re

# with open('test.bin', 'bw') as file:
#     file.write(b'Food\x01Fruit\x02Banana\x03Apple\x03Vegetable\x02Carrot\x03')

def insert(tree, path):
    node = tree
    for key in path:
        if not (key in node):
            node[key] = {}
        node = node[key]


def parse_file(filename):
    pattern = re.compile(b'([a-zA-Z]+)([\x01-\x1F])')
    result = {}
    tree_path = []
    with open(filename, 'rb') as file:
        data = file.read()
    for key, level in re.findall(pattern, data):
        tree_path[ord(level):] = [key]
        insert(result, tree_path)
    return result

assert parse_file('test.bin') == {b'Food': {b'Fruit': {b'Vegetable': {b'Carrot': {}}, b'Banana': {b'Apple': {}}}}}