title: where is the 'itertools' file
body: <pre><code>import itertools
  print itertools#ok
  </code></pre>
  
  <p>the code is ok</p>
  
  <p>but i can't find the itertools file.</p>
  
  <p>who can tell me where is the 'itertools file'</p>
  
  <hr>
  
  <p>my code is run python2.5</p>
  
  <pre><code>import itertools
  print itertools.__file__
  
  
  Traceback (most recent call last):
    File "D:\zjm_code\mysite\zjmbooks\a.py", line 5, in &lt;module&gt;
      print itertools.__file__
  AttributeError: 'module' object has no attribute '__file__'
  </code></pre>