code: public ItemRequest<Webhook> deleteById(String webhook) {
      
          String path = String.format("/webhooks/%s", webhook);
          return new ItemRequest<Webhook>(this, Webhook.class, path, "DELETE");
      }
docs: This method permanently removes a webhook. Note that it may be possible
  to receive a request that was already in flight after deleting the
  webhook, but no further requests will be issued.
  
  @param  webhook The webhook to delete.
  @return Request object