How to use the @aws-cdk/aws-appsync.CfnResolver function in @aws-cdk/aws-appsync

const getAllResolver = new CfnResolver(this, 'GetAllQueryResolver', {
      apiId: itemsGraphQLApi.attrApiId,
      typeName: 'Query',
      fieldName: 'all',
      dataSourceName: dataSource.name,
      requestMappingTemplate: `{
        "version": "2017-02-28",
        "operation": "Scan",
        "limit": $util.defaultIfNull($ctx.args.limit, 20),
        "nextToken": $util.toJson($util.defaultIfNullOrEmpty($ctx.args.nextToken, null))
      }`,
      responseMappingTemplate: `$util.toJson($ctx.result)`
    });
    getAllResolver.addDependsOn(apiSchema);

    const saveResolver = new CfnResolver(this, 'SaveMutationResolver', {
      apiId: itemsGraphQLApi.attrApiId,
      typeName: 'Mutation',
      fieldName: 'save',
      dataSourceName: dataSource.name,
      requestMappingTemplate: `{
        "version": "2017-02-28",
        "operation": "PutItem",
        "key": {
          "${tableName}Id": { "S": "$util.autoId()" }
        },
        "attributeValues": {
          "name": $util.dynamodb.toDynamoDBJson($ctx.args.name)
        }
      }`,
      responseMappingTemplate: `$util.toJson($ctx.result)`
    });

});

    itemsTableRole.addManagedPolicy(ManagedPolicy.fromAwsManagedPolicyName('AmazonDynamoDBFullAccess'));

    const dataSource = new CfnDataSource(this, 'ItemsDataSource', {
      apiId: itemsGraphQLApi.attrApiId,
      name: 'ItemsDynamoDataSource',
      type: 'AMAZON_DYNAMODB',
      dynamoDbConfig: {
        tableName: itemsTable.tableName,
        awsRegion: this.region
      },
      serviceRoleArn: itemsTableRole.roleArn
    });

    const getOneResolver = new CfnResolver(this, 'GetOneQueryResolver', {
      apiId: itemsGraphQLApi.attrApiId,
      typeName: 'Query',
      fieldName: 'getOne',
      dataSourceName: dataSource.name,
      requestMappingTemplate: `{
        "version": "2017-02-28",
        "operation": "GetItem",
        "key": {
          "${tableName}Id": $util.dynamodb.toDynamoDBJson($ctx.args.${tableName}Id)
        }
      }`,
      responseMappingTemplate: `$util.toJson($ctx.result)`
    });
    getOneResolver.addDependsOn(apiSchema);

    const getAllResolver = new CfnResolver(this, 'GetAllQueryResolver', {

dataSourceName: dataSource.name,
      requestMappingTemplate: `{
        "version": "2017-02-28",
        "operation": "PutItem",
        "key": {
          "${tableName}Id": { "S": "$util.autoId()" }
        },
        "attributeValues": {
          "name": $util.dynamodb.toDynamoDBJson($ctx.args.name)
        }
      }`,
      responseMappingTemplate: `$util.toJson($ctx.result)`
    });
    saveResolver.addDependsOn(apiSchema);

    const deleteResolver = new CfnResolver(this, 'DeleteMutationResolver', {
      apiId: itemsGraphQLApi.attrApiId,
      typeName: 'Mutation',
      fieldName: 'delete',
      dataSourceName: dataSource.name,
      requestMappingTemplate: `{
        "version": "2017-02-28",
        "operation": "DeleteItem",
        "key": {
          "${tableName}Id": $util.dynamodb.toDynamoDBJson($ctx.args.${tableName}Id)
        }
      }`,
      responseMappingTemplate: `$util.toJson($ctx.result)`
    });
    deleteResolver.addDependsOn(apiSchema);

  }

apiId: itemsGraphQLApi.attrApiId,
      typeName: 'Query',
      fieldName: 'getOne',
      dataSourceName: dataSource.name,
      requestMappingTemplate: `{
        "version": "2017-02-28",
        "operation": "GetItem",
        "key": {
          "${tableName}Id": $util.dynamodb.toDynamoDBJson($ctx.args.${tableName}Id)
        }
      }`,
      responseMappingTemplate: `$util.toJson($ctx.result)`
    });
    getOneResolver.addDependsOn(apiSchema);

    const getAllResolver = new CfnResolver(this, 'GetAllQueryResolver', {
      apiId: itemsGraphQLApi.attrApiId,
      typeName: 'Query',
      fieldName: 'all',
      dataSourceName: dataSource.name,
      requestMappingTemplate: `{
        "version": "2017-02-28",
        "operation": "Scan",
        "limit": $util.defaultIfNull($ctx.args.limit, 20),
        "nextToken": $util.toJson($util.defaultIfNullOrEmpty($ctx.args.nextToken, null))
      }`,
      responseMappingTemplate: `$util.toJson($ctx.result)`
    });
    getAllResolver.addDependsOn(apiSchema);

    const saveResolver = new CfnResolver(this, 'SaveMutationResolver', {
      apiId: itemsGraphQLApi.attrApiId,