title: How to select nth element in codeception
body: <p>I have a table with checkboxes in each row. The user can select some rows and delete them, also I have this "select all" checkbox. 
  I want to test selecting and deleting two rows for example, also click select all and delete them.
  So I need to check the second and third checkboxes for the first test and first one for the second test...</p>
  
  <p>I couldn't find a way to select the nth element, the only way I could find is selecting by xpath, so I tried this without luck:</p>
  
  <pre><code>$I-&gt;checkOption("(//input[@type='checkbox'])[2]");
  </code></pre>
  
  <p>The error is smt. like <code>//html(//input[@type='checkbox'])[2] is invalid</code>.
  Apparently codeception is modifying the selector, so I tried to use WebDriverBy class but I couldn't find a way to pass it as a parameter...</p>
  
  <p>Any ideas?</p>
  
  <p>PS: This is not the actual case but a simple example to describe the problem...</p>