static function instance( $module_id, $slug = false, $is_init = false ) {
            if ( empty( $module_id ) ) {
                return false;
            }

            /**
             * Load the essential static data prior to initiating FS_Plugin_Manager since there's an essential MS network migration logic that needs to be executed prior to the initiation.
             */
            self::_load_required_static();

            if ( ! is_numeric( $module_id ) ) {
                if ( ! $is_init && true === $slug ) {
                    $is_init = true;
                }

                $slug = $module_id;

                $module = FS_Plugin_Manager::instance( $slug )->get();

                if ( is_object( $module ) ) {
                    $module_id = $module->id;
                }
            }

            $key = 'm_' . $module_id;

            if ( ! isset( self::$_instances[ $key ] ) ) {
                self::$_instances[ $key ] = new Freemius( $module_id, $slug, $is_init );
            }

            return self::$_instances[ $key ];
        }