How to access function value in another function in PHP Classes

Question

How can I return a variable value from one function, pass it to another function in a class, and access it?

Code I have worked on:

<?php
class BioTool{
public function one(){
$lol =[2,3,5]; print_r($lol);
}
 public function two(){
     $newarr=$this->one(); //this only return the array but i can't access it, check below.
    print_r($newarr[0]); //not working
}
}

$biotool=new BioTool();
$biotool->two();

Can someone help me do this?