如何在Python中查找加起来达到某个数字的所有可能的字典值组合，同时仍然保留键名称

def find_combinations(dictionary, target_sum):
    result = []
    current_combination = {}

    def backtrack(dictionary, target_sum, current_sum, start_index):
        if current_sum == target_sum:
            result.append(current_combination.copy())
            return
        if current_sum > target_sum:
            return

        for i in range(start_index, len(dictionary)):
            key = list(dictionary.keys())[i]
            value = dictionary[key]
            current_combination[key] = value
            backtrack(dictionary, target_sum, current_sum + value, i + 1)
            del current_combination[key]

    backtrack(dictionary, target_sum, 0, 0)
    return result

dictionary = {'a': 1, 'b': 2, 'c': 3, 'd': 4}
target_sum = 5

combinations = find_combinations(dictionary, target_sum)
for combination in combinations:
    print(combination)

{'a': 1, 'b': 2}
{'c': 3, 'a': 1, 'b': 2}
{'d': 4, 'a': 1}