Fatal error: Uncaught TypeError: Return value of Urban\ProductAttachment\Controller\Download\Attachment::loadAttachmentById() must implement interface Urban\ProductAttachment\Api\Data\AttachmentInterface or be null, none returned in /var/www/html/app/code/Urban/ProductAttachment/Controller/Download/Attachment.php:112 Stack trace: #0 /var/www/html/app/code/Urban/ProductAttachment/Controller/Download/Attachment.php(72): Urban\ProductAttachment\Controller\Download\Attachment->loadAttachmentById(1444) #1 /var/www/html/lib/internal/Magento/Framework/App/Action/Action.php(107): Urban\ProductAttachment\Controller\Download\Attachment->execute() #2 /var/www/html/lib/internal/Magento/Framework/Interception/Interceptor.php(58): Magento\Framework\App\Action\Action->dispatch(Object(Magento\Framework\App\Request\Http)) #3 /var/www/html/lib/internal/Magento/Framework/Interception/Interceptor.php(144): Urban\ProductAttachment\Controller\Download\Attachment\Interceptor->___callParent('dispatch', Array) #4 /var/www/html/lib/internal/Magent in /var/www/html/app/code/Urban/ProductAttachment/Controller/Download/Attachment.php on line 112