If you want to use a class:
from datetime import datetime,timedelta
class MyThread():
def __init__(self, name, timeLimit):
self.name = name
self.timeLimit = timeLimit
def run(self):
# get the start time
startTime = datetime.now()
while True:
# stop if the time limit is reached :
if((datetime.now()-startTime)>self.timeLimit):
break
print('A')
mt = MyThread('aThread',timedelta(microseconds=20000))
mt.run()