BlogFactoryZendDbSqlRepositoryFactory.php

<?php
// In module/Blog/src/Factory/ZendDbSqlRepositoryFactory.php
namespace Blog\Factory;

use Interop\Container\ContainerInterface;
use Blog\Mapper\ZendDbSqlRepository;
use Zend\Db\Adapter\AdapterInterface;
use Zend\ServiceManager\Factory\FactoryInterface;

class ZendDbSqlRepositoryFactory implements FactoryInterface
{
    /**
     * @param ContainerInterface $container
     * @param string $requestedName
     * @param null|array $options
     * @return ZendDbSqlRepository
     */
    public function __invoke(ContainerInterface $container, $requestedName, array $options = null)
    {
        return new ZendDbSqlRepository($container->get(AdapterInterface::class)); // changed from ZendDbSqlMapper in docs
    }
}