title: An elegant and fast way to consecutively iterate over two or more containers in Python?
body: <p>I have three collection.deques and what I need to do is to iterate over each of them and perform the same action:</p>
  
  <pre><code>for obj in deque1:  
      some_action(obj)  
  
  for obj in deque2:  
      some_action(obj)
  
  for obj in deque3:  
      some_action(obj)
  </code></pre>
  
  <p>I'm looking for some function XXX which would ideally allow me to write:</p>
  
  <pre><code>for obj in XXX(deque1, deque2, deque3):  
      some_action(obj)
  </code></pre>
  
  <p>The important thing here is that XXX have to be efficient enough - without making copy or silently using range(), etc. I was expecting to find it in built-in functions, but I found nothing similar to it so far.</p>
  
  <p>Is there such thing already in Python or I have to write a function for that by myself?</p>