import time
# 将时间戳转换成格式化日期
def timestamp_to_str(timestamp=None, format='%Y-%m-%d %H:%M:%S'):
    if timestamp:
        time_tuple = time.localtime(timestamp)  # 把时间戳转换成时间元祖
        result = time.strftime(format, time_tuple)  # 把时间元祖转换成格式化好的时间
        return result
    else:
        return time.strptime(format)