public function getCategoriesFor(Collection $client_surveys, ?string $locale = null): array 	{ 		// These 3 columns are always present in rankings 		$category_list = [__('general-report-pdf.esi'), __('general-report-pdf.enps'), __('general-report-pdf.engagement')]; 		$categories = $client_surveys->first()?->getClientSurvey()->survey->categories;  		if ($categories === null) { 			return []; 		}  		foreach ($categories as $cat) { 			$category_list[] = $cat->getTranslation('name', $locale ?? DomainLanguages::getDefaultLanguage()); 		}  		return $category_list; 	}