code: func (c *Client) AddonDelete(appIdentity string, addonIdentity string) error {
  	return c.Delete("/apps/" + appIdentity + "/addons/" + addonIdentity)
  }
docs: // Delete an existing add-on.
  //
  // appIdentity is the unique identifier of the Addon's App. addonIdentity is the
  // unique identifier of the Addon.