new_contents: from Queue import Queue
  from threading import Thread
  
  # from http://code.activestate.com/recipes/577187-python-thread-pool/
  
  
  class Worker(Thread):
      """Thread executing tasks from a given tasks queue"""
      def __init__(self, tasks):
          Thread.__init__(self)
          self.tasks = tasks
          self.daemon = True
          self.start()
  
      def run(self):
          while True:
              func, args, kargs = self.tasks.get()
              try:
                  func(*args, **kargs)
              except Exception, e:
                  print e
              self.tasks.task_done()
  
  
  class ThreadPool:
      """Pool of threads consuming tasks from a queue"""
      def __init__(self, num_threads):
          self.tasks = Queue(num_threads)
          for _ in range(num_threads):
              Worker(self.tasks)
  
      def add_task(self, func, *args, **kargs):
          """Add a task to the queue"""
          self.tasks.put((func, args, kargs))
  
      def wait_completion(self):
          """Wait for completion of all the tasks in the queue"""
          self.tasks.join()
  
  """
  if __name__ == '__main__':
      from random import randrange
      delays = [randrange(1, 10) for i in range(100)]
  
      from time import sleep
  
      def wait_delay(d):
          print 'sleeping for (%d)sec' % d
          sleep(d)
  
      # 1) Init a Thread pool with the desired number of threads
      pool = ThreadPool(20)
  
      for i, d in enumerate(delays):
          # print the percentage of tasks placed in the queue
          print '%.2f%c' % ((float(i)/float(len(delays)))*100.0, '%')
  
          # 2) Add the task to the queue
          pool.add_task(wait_delay, d)
  
      # 3) Wait for completion
      pool.wait_completion()
  
  """
  
subject: add initial code for thread pool