public function define_plugin_structure($connectionpoint)
 {
     global $CFG;
     if (!$connectionpoint instanceof restore_path_element) {
         throw new restore_step_exception('restore_path_element_required', $connectionpoint);
     }
     //check if enabled at site level and plugin is enabled.
     require_once $CFG->libdir . '/plagiarismlib.php';
     $enabledplugins = plagiarism_load_available_plugins();
     if (!array_key_exists($this->pluginname, $enabledplugins)) {
         return array();
     }
     return parent::define_plugin_structure($connectionpoint);
 }