filter_id ?? null; if (isset($filter_id)) { return "/_ml/filters/$filter_id"; } return "/_ml/filters"; } public function getParamWhitelist(): array { return [ 'from', 'size' ]; } public function getMethod(): string { return 'GET'; } public function setFilterId($filter_id): GetFilters { if (isset($filter_id) !== true) { return $this; } $this->filter_id = $filter_id; return $this; } }