title: AttributeError: 'int' object has no attribute 'match' when I do reg exp
body: <p>I am trying to read a file and try the below regexp to find the existance of a particular string but then end up with the follow error.</p>
  
  <pre><code>if re.match("(.*)hello.%s_world"%(str(what_name)), lines):
  </code></pre>
  
  <p>Get the below error:</p>
  
  <pre><code>AttributeError: 'int' object has no attribute 'match'
  </code></pre>
  
  <p>What could be the basic error or issue ? Kindly clarify the same !</p>
  
  <p>Update: 
  When I copied the same file and tried as a small experiment it works fine. But when I try the same in my bigger script i get the above error !</p>