public function delete($id = null)
    {
        if (is_null($id) || is_array($id)) {
            return $this->deleteMany($id);
        }

        $response = $this->ontraport->delete(
            $this->getSingularNamespace(), $this->toArray(compact('id'))
        );

        return $this->ontraport->item($this, $response);
    }