simple pool trait

Pool.php

<?php

trait Pool
{
    /** @var array **/
    protected static $aPool = [];
    
    public static function addToPool($key, $val)
    {
        self::$aPool[$key] = $val;
    }
    
    public static function getFromPool($key)
    {
        return self::$aPool[$key] ?? null;
    }
    
    public static function existsInPool($key)
    {
        return isset(self::$aPool[$key]);
    }
    
    public static function getPool()
    {
        return self::$aPool;
    }
}