public function getSumByCategory(array $categories_scores): array 	{ 		$scores_sum_per_category = [];  		foreach ($categories_scores as $key => $scores) { 			if (!$key) { 				$scores_sum_per_category = $scores; 			} else { 				foreach ($scores as $key_score => $score) { 					$element = (float) $scores_sum_per_category[$key_score]; 					$scores_sum_per_category[$key_score] = number_format($element + (float) ($score), 10, '.'); 				} 			} 		}  		return $scores_sum_per_category; 	}