如果value与给定字典中的键相等，如何将第一个键的值附加到所述值的键

def append_value_if_key_matches(dictionary, key, value):
    for k, v in dictionary.items():
        if k == key:
            dictionary[k] += value
            break

# 示例用法
my_dict = {'a': [1, 2, 3], 'b': [4, 5, 6], 'c': [7, 8, 9]}
key_to_match = 'b'
value_to_append = [10, 11, 12]

append_value_if_key_matches(my_dict, key_to_match, value_to_append)

print(my_dict)

{'a': [1, 2, 3], 'b': [4, 5, 6, 10, 11, 12], 'c': [7, 8, 9]}