title: Python concurrent.futures - method not called
body: <p>I am running a local django server with the following code: </p>
  
  <pre><code>import concurrent.futures
  
  media_download_manager = concurrent.futures.ProcessPoolExecutor(max_workers=2)
  
  def hello():
      print "hello"
  
  
  for i in range(1, 1000):
      print "submitting task "
      media_download_manager.map(hello)
  </code></pre>
  
  <p>I am initializing a process pool executor to accept tasks with 2 worker threads. The tasks are being submitter but the worker threads handling the submitted tasks do not seem to have triggered. </p>
  
  <p>Following it the console output: </p>
  
  <pre><code>submitting task 1
  submitting task 2
  submitting task 3
  submitting task 4
  submitting task 5
  submitting task 6
  submitting task 7
  submitting task 8
  submitting task 9
  Performing system checks...
  
  System check identified no issues (0 silenced).
  October 15, 2016 - 06:09:31
  Django version 1.8.4, using settings 'Learn.settings'
  Starting development server at http://192.168.1.3:8000/
  Quit the server with CONTROL-C.
  </code></pre>
  
  <p>What am I missing here ?</p>