text: # -*- coding: utf-8 -*-
  # Copyright (c) 2017-18 Richard Hull and contributors
  # See LICENSE.rst for details.
  
  # Adapted from http://code.activestate.com/recipes/577187-python-thread-pool/
  # Attribution: Created by Emilio Monti on Sun, 11 Apr 2010 (MIT License).
  
  from threading import Thread
  
  
  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()
              func(*args, **kargs)
              self.tasks.task_done()
  
  
  class threadpool:
      """Pool of threads consuming tasks from a queue."""
  
      def __init__(self, num_threads):
          try:
              from Queue import Queue
          except ImportError:
              from queue import Queue
  
          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()
  