public static function is_mlbackend_used($plugin) {
        $models = self::get_all_models();
        foreach ($models as $model) {
            $processor = $model->get_predictions_processor();
            $noprefixnamespace = ltrim(get_class($processor), '\\');
            $processorplugin = substr($noprefixnamespace, 0, strpos($noprefixnamespace, '\\'));
            if ($processorplugin == $plugin) {
                return true;
            }
        }

        // Default predictions processor.
        $defaultprocessorclass = get_config('analytics', 'predictionsprocessor');
        $pluginclass = '\\' . $plugin . '\\processor';
        if ($pluginclass === $defaultprocessorclass) {
            return true;
        }

        return false;
    }