title: For loop behavior
body: <p>This is strange. </p>
  
  <pre><code>a = range(10)
  
  def remove_pop():
    global a
    a.pop()
  
  for i in a:
    remove_pop()
    print i,
  
  print '\n',a
  
  0 1 2 3 4 
  [0, 1, 2, 3, 4]
  </code></pre>
  
  <p>Why did the loop exit prematurely ? Shouldn't it quit only after <code>a</code> gets emptied ?</p>