protected function getFieldDefinition(array $data)
    {
        $contentTypeId = $this->requestParser->parseHref($data['__url'], 'contentTypeId');
        $fieldDefinitionId = $this->requestParser->parseHref($data['__url'], 'fieldDefinitionId');

        $contentTypeDraft = $this->contentTypeService->loadContentTypeDraft($contentTypeId);
        foreach ($contentTypeDraft->getFieldDefinitions() as $fieldDefinition) {
            if ($fieldDefinition->id == $fieldDefinitionId) {
                return $fieldDefinition;
            }
        }
        throw new Exceptions\NotFoundException("Field definition not found: '{$data['__url']}'.");
    }