source: sipes/modules_contrib/token/token.install

<?php

/**
 * @file
 * The install and update code for the token module.
 *
 * @ingroup token
 */

/**
 * Implements hook_requirements().
 */
function token_requirements($phase = 'runtime') {
  $requirements = array();
  $t = get_t();

  // Check for duplicate tokens.
  if ($phase == 'runtime') {
    if ($duplicate_tokens = token_find_duplicate_tokens()) {
      foreach ($duplicate_tokens as $token => $modules) {
        $duplicate_tokens[$token] = $t('@token (defined by modules: @modules)', array('@token' => $token, '@modules' => implode(', ', $modules)));
      }
      $requirements['token_duplicates'] = array(
        'title' => $t('Duplicate tokens'),
        'value' => $t('The following tokens are defined by multiple modules and may cause problems when performing token replacement.'),
        'severity' => REQUIREMENT_WARNING,
        'description' => theme('item_list', $duplicate_tokens),
      );
    }
  }

  return $requirements;
}

function token_install() {
  db_query("UPDATE {system} SET weight = 10 WHERE name = 'token'");
}

function token_update_1() {
  $ret = array();
  $ret[] = update_sql("UPDATE {system} SET weight = 10 WHERE name = 'token'");
  return $ret;
}