I create a module in magento 2 to test Graphql, but it’s not work.

my schema.graphqls

#Coppy codilar Blog
type Query{
    codilarblog: Codilarblog @resolver(class : "Codilar\GraphQlDemo\Model\Resolver\Blog") @doc(description: " the query return something")
}

type Codilarblog @doc(description : "Codilarblog defines the blog name and "){
    entity_id: Int
    blog_name: String
    author: String
    blog_content : String
}

my Resolver/Blog

<?php

namespace CodilarGraphQlDemoModelResolver;

use MagentoFrameworkGraphQlConfigElementField;
use MagentoFrameworkGraphQlQueryResolverContextInterface;
use MagentoFrameworkGraphQlQueryResolverValue;
use MagentoFrameworkGraphQlQueryResolverValueFactory;
use MagentoFrameworkGraphQlQueryResolverInterface;
use MagentoFrameworkGraphQlSchemaTypeResolveInfo;

class Blog implements ResolverInterface
{
    /**
     * @var ValueFactory
     */
    private $valueFactory;

    /**
     * Blog constructor.
     * @param ValueFactory $valueFactory
     */
    public function __construct(ValueFactory $valueFactory)
    {
        $this->valueFactory = $valueFactory;
    }

    /**
     * @param Field $field
     * @param ContextInterface $context
     * @param ResolveInfo $info
     * @param array|null $value
     * @param array|null $args
     * @return Value|mixed
     * @throws Exception
     */
    public function resolve(Field $field, $context, ResolveInfo $info, array $value = null, array $args = null)
    {
        try {
            $blog = $this->getBlogArray();
            $result = function () use ($blog) {
                return !empty($blog) ? $blog : [];
            };
            return $this->valueFactory->create($result);
        } catch (Exception $exception) {
            throw new Exception(__($exception->getMessage()));
        }
    }

    /**
     * @return array
     */
    public function getBlogArray()
    {
        $blog = [
            'entity_id' => 1,
            'blog_name' => 'Some blog name',
            'author' => 'Some Author Name',
            'blog_content' => 'Hi, this is blog content.'
        ];
        return $blog;
    }
}

my folder module

error after i upgrade and run :