如何在python中添加HH:MM:SS，XX格式的时间

from datetime import datetime, timedelta

def add_time(time_str, hours=0, minutes=0, seconds=0):
    # 将时间字符串转换为datetime对象
    time_obj = datetime.strptime(time_str, "%H:%M:%S,%f")
    
    # 添加指定的小时、分钟和秒数
    time_obj += timedelta(hours=hours, minutes=minutes, seconds=seconds)
    
    # 将结果格式化为HH:MM:SS，XX格式的时间字符串
    new_time_str = time_obj.strftime("%H:%M:%S,%f")[:-3]
    
    return new_time_str

# 示例用法
time_str = "12:34:56,789"
new_time_str = add_time(time_str, hours=1, minutes=30)
print(new_time_str)