title: pass more than one function to a callback
body: <p>Given that :</p>
  
  <pre><code>with concurrent.futures.ProcessPoolExecutor(max_workers=(2*multiprocessing.cpu_count()+1)) as executor:
          for netelement in DOC['code']['info']['dev']:
              job = executor.submit(bgp_communities.do_lookup, netelement)
              job.add_done_callback(functools.partial(bgp_communities.do_data_wrangling, DOC))
  </code></pre>
  
  <p>is it possible to pass a 2nd function (like <code>bgp_communities.do_data_wrangling</code>) as a parameter to the callback of the <code>future</code> ?</p>