public function calculateClientSurveyGradeForSpecificCategories(ClientSurvey $client_survey, Collection $answers, Collection $categories): string 	{ 		$applicantIds = $client_survey->applicants->pluck('id')->toArray();  		$engagementCategoryIds = $client_survey->getEngagementCategoryIds();  		$answersCollection = Answer::groupBy('applicant_id') 		->whereIn('id', $answers->pluck('id')->all()) 		->whereIn('applicant_id', $applicantIds) 		->whereHas('question', function ($query) use ($engagementCategoryIds) { 			$query->whereIn('category_id', $engagementCategoryIds); 		}) 		->select(DB::raw('applicant_id, avg(answer_value) as answer_value_average')) 		->get();  		return number_format($answersCollection->avg('answer_value_average'), 3); 	}