spot the bug

uuid.entity.php

/**
 * Implements of hook_entity_property_info_alter().
 *
 * This adds the UUID as an entity property for all UUID-enabled entities
 * which automatically gives us token and Rules integration.
 */
function uuid_entity_property_info_alter(&$info) {
  foreach (entity_get_info() as $entity_type => $info) {
    if (isset($info['uuid']) && $info['uuid'] == TRUE && !empty($info['entity keys']['uuid'])) {
      $info[$entity_type]['properties'][$info['entity keys']['uuid']] = array(
        'label' => t('UUID'),
        'type' => 'text',
        'description' => t('The universally unique ID.'),
        'schema field' => $info['entity keys']['uuid'],
      );
      if (!empty($info['entity keys']['revision uuid'])) {
        $info[$entity_type]['properties'][$info['entity keys']['revision uuid']] = array(
          'label' => t('Revision UUID'),
          'type' => 'text',
          'description' => t("The revision's universally unique ID."),
          'schema field' => $info['entity keys']['revision uuid'],
        );
      }
    }
  }
}