A repeating timer in Python

repeatingtimer.py

class RepeatingTimer(object):
	"""
	USAGE:
	from time import sleep
	def myFunction(inputArgument):
		print(inputArgument)
	
	r = RepeatingTimer(0.5, myFunction, "hello")
	r.start(); sleep(2); r.interval = 0.05; sleep(2); r.stop()
	"""

	def __init__(self,interval, function, *args, **kwargs):
		super(RepeatingTimer, self).__init__()
		self.args = args
		self.kwargs = kwargs
		self.function = function
		self.interval = interval

	def start(self):
		self.callback()
		
	def stop(self):
		self.interval = False
		
	def callback(self):
		if self.interval:
			self.function(*self.args, **self.kwargs)
			Timer(self.interval, self.callback, ).start()

from threading import Timer
import time

class RepeatingTimer(object):
"""
USAGE:
from time import sleep
r = RepeatingTimer(_print, 0.5, "hello")
r.start(); sleep(2); r.interval = 0.05; sleep(2); r.stop()
"""

def __init__(self, function, interval, *args, **kwargs):
    super(RepeatingTimer, self).__init__()
    self.args = args
    self.kwargs = kwargs
    self.function = function
    self.interval = interval

def start(self):
    self.callback()
    
def stop(self):
    self.interval = False
    
def callback(self):
    if self.interval:
        self.function(*self.args, **self.kwargs)
        Timer(self.interval, self.callback, ).start()

def dowork():
global count
count = count + 1

count = 0
timer = RepeatingTimer(dowork, 0.0001)
timer.start()
time.sleep(1.0)
timer.stop()

print(count)
output:
3039

The theoretical output should be 10000. But here it is 3039. I'm not understanding why!