title: find substring between "a" and "(" + 2 unknown characters +")"
body: <p>I have some strings which are built this way:</p>
  
  <pre><code>string = "blabla y the_blabla_I_want (two_digits_number) blabla"
  </code></pre>
  
  <p>I would like to get the_blabla_I_want. 
  I know the <code>re.search</code> can help but my problem is about how to represent <code>(two_digits_number)</code>.</p>