Python threading object self._stop () "Event" could not be called

Trying to "stop" a thread from a StackOverflow question like this:

import sys
import threading
import time
import logging

class StoppableThread(threading.Thread):
    """Thread class with a stop() method. The thread itself has to check
    regularly for the stopped() condition."""

    def __init__(self):
        print( "base init", file=sys.stderr )
        super(StoppableThread, self).__init__()
        self._stop = threading.Event()

    def stop(self):
        print( "base stop()", file=sys.stderr )
        self._stop.set()

    def stopped(self):
        return self._stop.is_set()


class datalogger(StoppableThread):
    """
    """

    import time

    def __init__(self, outfile):
      """
      """
      StoppableThread.__init__(self)
      self.outfile = outfile
      print( "thread init", file=sys.stderr )

    def run(self):
      """
      """
      print( "thread running", file=sys.stderr )
      while not self.stopped():
        print( self.outfile , file=sys.stderr)
        time.sleep(0.33)
      print( "thread ending", file=sys.stderr )


test = datalogger("test.txt")
test.start()
time.sleep(3)
logging.debug("stopping thread")
test.stop()
logging.debug("waiting for thread to finish")
test.join()

      

        
        
        
      

    

gives the following error result:

> demo.py
base init
thread init
thread running
test.txt
test.txt
test.txt
test.txt
test.txt
test.txt
test.txt
test.txt
test.txt
test.txt
base stop()
thread ending
Traceback (most recent call last):
  File "demo.py", line 54, in <module>
    test.join()
  File "C:\Python34\lib\threading.py", line 1061, in join
    self._wait_for_tstate_lock()
  File "C:\Python34\lib\threading.py", line 1079, in _wait_for_tstate_lock
    self._stop()
TypeError: 'Event' object is not callable

      

        
        
        
      

    

Can someone please explain what I am doing wrong?

Doc: https://docs.python.org/3.4/library/threading.html#event-objects