title: how to delete a part of a text in python
body: <p>I am pretty new to python so got stuck in this problem:</p>
  
  <p>there is a txt file like</p>
  
  <pre><code>blahh
  blah
  blah 
  ...
  &lt;start&gt;
   some stuff
  &lt;/start&gt;
  even more blah blah blah
  </code></pre>
  
  <p>I want to delete all the blah parts before the <code>&lt;start&gt;</code> and after the <code>&lt;/start&gt;</code>. (The main thing is coming from this <a href="http://www.sec.gov/Archives/edgar/data/70858/000119312507058027/0001193125-07-058027.txt" rel="nofollow">link</a>. I want to make the html stuff in the page by bs4, so I think I must first delete all the non-html parts.</p>
  
  <p>Can someone please tell me What is the best way to do this? Appreciate any helps!</p>