protected function getTransformers()
    {
        $out = [];

        foreach ($this->transformers as $transformer) {
            if ($transformer instanceof Transformer) {
                $out[] = $transformer;
            } else if (is_string($transformer)) {
                $out[] = TransformerLibrary::make($transformer);
            } else {
                throw new LogicException("All transformers must implement " . Transformer::class);
            }
        }

        return $out;
    }