function array_sum_intervals($array_external, $intervals){

        $n_intervals=explode(";", $intervals);
        $array_amount = count($n_intervals);
        $result = 0;
        for($i=0; $i < $array_amount ; $i++){
            $result += $this->array_sum_interval($array_external, $n_intervals[$i]);
        }
        return $result;

    }