code: func (c *Client) AppFeatureList(appIdentity string, lr *ListRange) ([]AppFeature, error) {
  	req, err := c.NewRequest("GET", "/apps/"+appIdentity+"/features", nil, nil)
  	if err != nil {
  		return nil, err
  	}
  
  	if lr != nil {
  		lr.SetHeader(req)
  	}
  
  	var appFeaturesRes []AppFeature
  	return appFeaturesRes, c.DoReq(req, &appFeaturesRes)
  }
docs: // List existing app features.
  //
  // appIdentity is the unique identifier of the AppFeature's App. lr is an
  // optional ListRange that sets the Range options for the paginated list of
  // results.