public function getByProject($project_id, $filter = 'all')
    {
        $project_id = (int) $project_id;
        if ($project_id <= 0) {
            throw new Exception('Invalid param project_id');
        }
        return $this->rest->get(
            "projects/$project_id/$this->action",
            $this->getParams($filter)
        );
    }