title: Python Threading with Event object
body: <p>I've seen a lot of Python scripts that use Threads in a class and a lot of them use the <code>threading.Event()</code>. For example:</p>
  
  <pre><code>class TimerClass(threading.Thread):
      def __init__(self):
          threading.Thread.__init__(self)
          self.event = threading.Event()
  
      def run(self):
          while not self.event.is_set():
              print "something"
              self.event.wait(120)
  </code></pre>
  
  <p>In the <code>while</code> loop, why do they check the condition if they don't set <code>self.event</code>?</p>