from datetime import datetime
# 获取当前时间
now = datetime.now()
# 设置一个时间点
time_point = datetime(2023, 5, 2, 4, 59, 0)
# 计算时间差，以秒为单位
difference = (now - time_point).total_seconds()
print(difference)

time_point在绝大多数情况下不会是这种写死的形式，可能是比如从读取一个文件的创建时间

if os.path.isfile(LockFile)==True:
    LockTime = os.path.getmtime(LockFile)
    timeStruce = time.localtime(LockTime)
    LockTime_Y = time.strftime('%Y', timeStruce)
    LockTime_m = time.strftime('%m', timeStruce)
    LockTime_d = time.strftime('%d', timeStruce)
    LockTime_H = time.strftime('%H', timeStruce)
    LockTime_M = time.strftime('%M', timeStruce)
    LockTime_S = time.strftime('%S', timeStruce)
    time_point = datetime(int(LockTime_Y), int(LockTime_m), int(LockTime_d), int(LockTime_H), int(LockTime_M), int(LockTime_S))

要用上面这段要记得先

import os
import time

定义LockFile也是必须的