如何制作列的所有组合

def generate_combinations(items):
    combinations = []
    generate_combinations_helper(items, [], combinations)
    return combinations

def generate_combinations_helper(items, current_combination, combinations):
    if len(items) == 0:
        combinations.append(current_combination)
    else:
        for i in range(len(items)):
            new_combination = current_combination + [items[i]]
            remaining_items = items[:i] + items[i+1:]
            generate_combinations_helper(remaining_items, new_combination, combinations)

items = [1, 2, 3]
combinations = generate_combinations(items)
for combination in combinations:
    print(combination)

[1, 2, 3]
[1, 3, 2]
[2, 1, 3]
[2, 3, 1]
[3, 1, 2]
[3, 2, 1]