title: how to skip error in python multiprocessing
body: <p>I use to run long independent jobs with multiprocessing.Pool.map</p>
  
  <pre><code>import multiprocessing
  pool = multiprocessing.Pool(multiprocessing.cpu_count())
  input_var = [1,2,3]
  ris = pool.map(long_function,input_var)
  pool.close()
  pool.join()
  </code></pre>
  
  <p>This works well but if for example I get an error in <code>long_function(2)</code> I will lose all the information that I have obtained with <code>long_function(1)</code> and <code>long_function(3)</code>. </p>
  
  <p>is there a way to avoid this? </p>
  
  <p>The best would be to obtain an output like <code>ris=[long_function(1), ERROR, long_function(3)]</code> 
  Is there anyway to do that?</p>