diff --git a/classes/cache_administration_helper.php b/classes/cache_administration_helper.php
index cc70646..0823985 100644
--- a/classes/cache_administration_helper.php
+++ b/classes/cache_administration_helper.php
@@ -75,10 +75,10 @@ public function get_definition_actions(context $context, array $definitionsummar
      * This function performs all of the outputting for the cache admin page,
      * with some custom tweaks for the plugin.
      *
-     * @param \core_cache\output\renderer $renderer
+     * @param core_cache_renderer $renderer
      * @return string HTML for the page;
      */
-    public function generate_admin_page(\core_cache\output\renderer $renderer): string {
+    public function generate_admin_page(core_cache_renderer $renderer): string {
         $context = context_system::instance();
         $html = '';
 
@@ -328,31 +328,4 @@ public static function instance(): core_cache\administration_helper {
         }
         return self::$instance;
     }
-
-    /**
-     * Gets usage information about the whole cache system.
-     *
-     * This is a slow function and should only be used on an admin information page.
-     *
-     * The returned array lists all cache definitions with fields 'cacheid' and 'stores'. For
-     * each store, the following fields are available:
-     *
-     * - name (store name)
-     * - class (e.g. cachestore_redis)
-     * - supported (true if we have any information)
-     * - items (number of items stored)
-     * - mean (mean size of item)
-     * - sd (standard deviation for item sizes)
-     * - margin (margin of error for mean at 95% confidence)
-     * - storetotal (total usage for store if known, otherwise null)
-     *
-     * The storetotal field will be the same for every cache that uses the same store.
-     *
-     * @param int $samplekeys Number of keys to sample when checking size of large caches
-     * @return array Details of cache usage
-     */
-    public function get_usage(int $samplekeys): array {
-        $corehelper = new core_cache\local\administration_display_helper();
-        return $corehelper->get_usage($samplekeys);
-    }
 }