private function activate_parent_account( Freemius $parent_fs ) {
            if ( ! $this->is_addon() ) {
                // This is not an add-on.
                return;
            }

            if ( $parent_fs->is_registered() ) {
                // Already activated.
                return;
            }

            // Activate parent with add-on's user credentials.
            $parent_install = $this->get_api_user_scope()->call(
                "/plugins/{$parent_fs->_plugin->id}/installs.json",
                'post',
                $parent_fs->get_install_data_for_api( array(
                    'uid' => $parent_fs->get_anonymous_id(),
                ), false, false )
            );

            if ( isset( $parent_install->error ) ) {
                $this->_admin_notices->add(
                    sprintf( $this->get_text_inline( 'Couldn\'t activate %s.', 'could-not-activate-x' ), $this->get_plugin_name() ) . ' ' .
                    $this->get_text_inline( 'Please contact us with the following message:', 'contact-us-with-error-message' ) . ' ' . '<b>' . $parent_install->error->message . '</b>',
                    $this->get_text_x_inline( 'Oops', 'exclamation', 'oops' ) . '...',
                    'error'
                );

                return;
            }

            $parent_fs->_admin_notices->remove_sticky( 'connect_account' );

            if ( $parent_fs->is_pending_activation() ) {
                $parent_fs->_admin_notices->remove_sticky( 'activation_pending' );

                unset( $parent_fs->_storage->is_pending_activation );
            }

            // Get user information based on parent's plugin.
            $user = $this->get_user();

            // First of all, set site info - otherwise we won't
            // be able to invoke API calls.
            $parent_fs->_site = new FS_Site( $parent_install );
            $parent_fs->_user = $user;

            // Sync add-on plans.
            $parent_fs->_sync_plans();

            $parent_fs->_set_account( $user, $parent_fs->_site );
        }