چطور در سالیدیتی شماره اسلات متغیر را بدست بیاوریم؟

// SPDX-License-Identifier: GPL-3.0
pragma solidity >=0.8.0 <0.9.0;

contract SlotLocation{
    uint256 private fourth;
    uint256 private third;
    uint256 private second; 
    uint256 private first;

    function storageLocation() external pure returns(uint256,uint256) {
        uint256 first_slotLocation;
        uint256 fourth_slotLocation;

        assembly {
            first_slotLocation := first.slot
            fourth_slotLocation := fourth.slot
        }

        return (first_slotLocation,fourth_slotLocation);
    }
}