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

constructor(scope: cdk.Construct, id: string, props?: cdk.StackProps) {
    super(scope, id, props);

    const tableName = 'items'

    const itemsGraphQLApi = new CfnGraphQLApi(this, 'ItemsApi', {
      name: 'items-api',
      authenticationType: 'API_KEY'
    });

    new CfnApiKey(this, 'ItemsApiKey', {
      apiId: itemsGraphQLApi.attrApiId
    });

    const apiSchema = new CfnGraphQLSchema(this, 'ItemsSchema', {
      apiId: itemsGraphQLApi.attrApiId,
      definition: `type ${tableName} {
        ${tableName}Id: ID!
        name: String
      }
      type Paginated${tableName} {
        items: [${tableName}!]!
        nextToken: String
      }
      type Query {
        all(limit: Int, nextToken: String): Paginated${tableName}!
        getOne(${tableName}Id: ID!): ${tableName}