eventespresso / event-espresso-core

        $message_template_group = EEM_Message_Template_Group::instance()->get_one_by_ID(

            $this->_req_data['message_template_group_id']

        );

        if (! $message_template_group instanceof EE_Message_Template_Group) {

            EE_Error::add_error(

                sprintf(

                    esc_html__(

                        'Unable to change the active state because the given id "%1$d" does not match a valid "%2$s"',

                        'event_espresso'

                    ),

                    $this->_req_data['message_template_group_id'],

                    'EE_Message_Template_Group'

                ),

                __FILE__,

                __FUNCTION__,

                __LINE__

            );

            $success = false;

        }

        if ($success) {

            $success = $status === 'off'

                ? $message_template_group->deactivate_context($this->_req_data['context'])

        );

        // grab the related ticket object for this line_item

        $ticket = $line_item->ticket();

        if (! $ticket instanceof EE_Ticket) {

            EE_Error::add_error(

                sprintf(

                    esc_html__('Line item %s did not contain a valid ticket', 'event_espresso'),

                    $line_item->ID()

                ),

                __FILE__,

                __FUNCTION__,

                __LINE__

            );

            return null;

        }

        $registration_service = new CreateRegistrationService();

        // then generate a new registration from that

        return $registration_service->create(

                    // add relation to registration, set attendee ID, and cache attendee

                    $this->_associate_attendee_with_registration($registration, $attendee);

                    // \EEH_Debug_Tools::printr( $registration, '$registration', __FILE__, __LINE__ );

                    if (! $registration->attendee() instanceof EE_Attendee) {

                        EE_Error::add_error(

                            sprintf(

                                esc_html__(

                                    'Registration %s has an invalid or missing Attendee object.',

                                    'event_espresso'

                                ),

                                $reg_url_link

                            ),

                            __FILE__,

                            __FUNCTION__,

                            __LINE__

                        );

                        return false;

                    }

                    /** @type EE_Registration_Processor $registration_processor */

                    $registration_processor = EE_Registry::instance()->load_class('Registration_Processor');

                    // at this point, we should have enough details about the registrant to consider the registration

            : null;

        $this->_transaction->verify_abandoned_transaction_status();

        if (! $this->_transaction instanceof EE_Transaction) {

            $error_msg = sprintf(

                esc_html__(

                    'An error occurred and the details for the transaction with the ID # %d could not be retrieved.',

                    'event_espresso'

                ),

                $TXN_ID

            );

            EE_Error::add_error($error_msg, __FILE__, __FUNCTION__, __LINE__);

        }

    }