无法在Python中拆分、追加和排序

string = "Hello, World!"
split_string = string.split(",")  # 以逗号为分隔符拆分字符串
print(split_string)  # 输出：['Hello', ' World!']

string = "Hello"
appended_string = string + ", World!"  # 字符串拼接
print(appended_string)  # 输出：Hello, World!

string = "cba"
sorted_string = ''.join(sorted(string))  # 将字符串转换为列表，排序后再转换为字符串
print(sorted_string)  # 输出：abc