Exported objects added to non-existant array

Any time an object is exported using the BulkExporter it is added to an array that doesn't exist, e.g.:

<?php
// $Id: $

/**
 * @file
 * Bulk export of panels_default objects generated by Bulk export module.
 */

/**
 * Implementation of hook_default_panels_mini()
 */
function mymodule_default_panels_mini() {
  $mini = new stdClass;
  $mini->name = 'thingy';
// ... definition ...
  $mini->display = $display;
  $minis['thingy'] = $mini;

 return $minis;
}

As you can see above the $mini object is added to the $minis array, but $minis was never defined.

Also, there's only one space before the 'return' command.