keyForAttribute(attr) {
    if (attr === "id") {
      return this.keyForId();
    }

    return attr;
  }
Used to customize how a model's attribute is formatted in your JSON payload.

    By default, model attributes are camelCase:

    ```
    GET /authors/1

    {
      author: {
        firstName: 'Link',
        lastName: 'The WoodElf'
      }
    }
    ```

    If your API expects snake case, you could write the following:

    ```js
    // serializers/application.js
    export default Serializer.extend({
      keyForAttribute(attr) {
        return underscore(attr);
      }
    });
    ```

    Now the response would look like:

    ```
    {
      author: {
        first_name: 'Link',
        last_name: 'The WoodElf'
      }
    }
    ```

    @method keyForAttribute
    @param attr
    @public