error in forums module when upgrading

OK this update calls it but I found no taxonomy_get_vocabularies function in the script.

function forum_update_6000() {
  $ret = array();

  $vid = variable_get('forum_nav_vocabulary', 0);
  $vocabularies = taxonomy_get_vocabularies();
  if (!isset($vocabularies[$vid])) {
    $vocabulary = array(
      'name' => t('Forums'),
      'multiple' => 0,
      'required' => 0,
      'hierarchy' => 1,
      'relations' => 0,
      'module' => 'forum',
      'weight' => -10,
      'nodes' => array('forum' => 1),
    );
    taxonomy_save_vocabulary($vocabulary);

    variable_set('forum_nav_vocabulary', $vocabulary['vid']);
  }

  return $ret;
}

OK I found the function in the Taxonomy API page, added it to forum.install and the update.php worked.