title: Include code snippet in org file
body: <p>I'm wanting to use org mode to write a technical book. I'm looking for a way to insert existing code from external file into a babel code block that would give nice formatting when exporting to pdf. </p>
  
  <p>For example </p>
  
  <pre><code>#+BEGIN_SRC python "./code/foo.py" 
    # insert_line (45,50)
  #+END_SRC
  </code></pre>
  
  <p>would then give me the equivalent of the following from line 45 to 50 in <code>foo.py</code></p>
  
  <pre><code>#+BEGIN_SRC python
   def times_two(x):
     y = x*2
     return y
  
   print times_two(5)    
  #+END_SRC
  </code></pre>
  
  <p>Is there anyway of doing this?</p>