import threading
def fun_timer():
  print('Hello Timer!')
timer = threading.Timer(1, fun_timer)
timer.start()

Hello Timer!
Process finished with exit code 0

"""Call a function after a specified number of seconds"""

def fun_timer():
  print('Hello Timer!')
  global timer
  timer = threading.Timer(5.5, fun_timer)
  timer.start()

timer = threading.Timer(1, fun_timer)
timer.start()

Hello Timer!
Hello Timer!
Hello Timer!
Hello Timer!
............

print(type(fun_timer()))
print(type(fun_timer))

Hello Timer!
<class 'NoneType'>
<class 'function'>

# -*- coding: utf-8 -*-
import threading
import time
def fun_timer():
  print('Hello Timer!')
  global timer
  timer = threading.Timer(5.5, fun_timer)
  timer.start()
timer = threading.Timer(1, fun_timer)
timer.start()
time.sleep(15) # 15秒后停止定时器
timer.cancel()

Hello Timer!
Hello Timer!
Hello Timer!
Process finished with exit code 0

# -* coding: utf-8 -*-
import sys
import os
import getopt
import threading
import time
def Usage():
 usage_str = '''说明：
 \t定时器
 \timer.py -h 显示本帮助信息，也可以使用--help选项
 \timer.py -d num 指定一个延时时间（以毫秒为单位）
 \t          也可以使用--duration=num选项
 '''
 print(usage_str)
 
def args_proc(argv):
 '''处理命令行参数'''
 try:
  opts, args = getopt.getopt(sys.argv[1:], 'hd:', ['help', 'duration='])
 except getopt.GetoptError as err:
  print('错误！请为脚本指定正确的命令行参数。\n')
  Usage()
  sys.exit(255)
 if len(opts) < 1:
  print('使用提示：缺少必须的参数。')
  Usage()
  sys.exit(255)
 usr_argvs = {}
 for op, value in opts:
  if op in ('-h', '--help'):
   Usage()
   sys.exit(1)
  elif op in ('-d', '--duration'):
   if int(value) <= 0:
    print('错误！指定的参数值%s无效。\n' % (value))
    Usage()
    sys.exit(2)
   else:
    usr_argvs['-d'] = int(value)
  else:
   print('unhandled option')
   sys.exit(3)
 return usr_argvs
def timer_proc(interval_in_millisecond):
 loop_interval = 10  # 定时精度，也是循环间隔时间（毫秒），也是输出信息刷新间隔时间，它不能大于指定的最大延时时间，否则可能导致无任何输出
 t = interval_in_millisecond / loop_interval
 while t >= 0:
  min = (t * loop_interval) / 1000 / 60
  sec = (t * loop_interval) / 1000 % 60
  millisecond = (t * loop_interval) % 1000
  print('\rThe remaining time:d:d:d...' % ( min, sec, millisecond ), end = '\t\t')
  time.sleep(loop_interval / 1000)
  t -= 1
 if millisecond != 0:
  millisecond = 0
  print('\rThe remaining time:d:d:d...' % ( min, sec, millisecond ), end = '\t\t')
 print()
# 应用程序入口
if __name__ == '__main__':
 usr_argvs = {}
 usr_argvs = args_proc(sys.argv)
 for argv in usr_argvs:
  if argv in ( '-d', '--duration'):
   timer_proc(usr_argvs[argv])
  else:
   continue