array_smart_merge function already defined in hierarchical_select module

Hi, I installed ahah_helper module and got error message that says array_smart_merge function already defined. I searched through my drupal installation and found that array_smart_merge function defined in hierarchical_select module.

I think the solution for these to modules (probably more in future) is to check whether the function is exist. If it exists, do nothing. But if not, then define it.

<?php
if (function_exists('array_smart_merge')) {
  function array_smart_merge($array, $override) {
    // function content
  }
}