General Thread for practicing question formatting!

[kshtzb1]

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.8;

import "@chainlink/contracts/src/v0.8/interfaces/AggregatorV3Interface.sol";
import "./PriceConverter.sol";


// 812,034
// 839,113

error NotOwner();
contract FundMe {
    using PriceConverter for uint256;

    mapping(address => uint256) public addressToAmountFunded;
    address[] public funders;

    // Could we make this constant?  /* hint]: no! We should make it immutable! */
    address public  immutable i_owner;
    uint256 public constant MINIMUM_USD = 50 * 10 ** 18;
    
    constructor() {
        i_owner = msg.sender;
    }

    function fund() public payable {
        require(msg.value.getConversionRate() >= MINIMUM_USD, "You need to spend more ETH!");
        // require(PriceConverter.getConversionRate(msg.value) >= MINIMUM_USD, "You need to spend more ETH!");
        addressToAmountFunded[msg.sender] += msg.value;
        funders.push(msg.sender);
    }
    
    function getVersion() public view returns (uint256){
        // ETH/USD price feed address of Sepolia Network.
        AggregatorV3Interface priceFeed = AggregatorV3Interface(0x694AA1769357215DE4FAC081bf1f309aDC325306);
        return priceFeed.version();
    }


      function withdraw() public onlyOwner {
        for (uint256 funderIndex=0; funderIndex < funders.length; funderIndex++){
            address funder = funders[funderIndex];
            addressToAmountFunded[funder] = 0;
        }
        funders = new address[](0);
        // // transfer
        // payable(msg.sender).transfer(address(this).balance);
        // // send
        // bool sendSuccess = payable(msg.sender).send(address(this).balance);
        // require(sendSuccess, "Send failed");
        // call
        //  It's attempting to send the entire balance of the contract to the owner.
        (bool callSuccess, ) = payable(msg.sender).call{value: address(this).balance}("");
        require(callSuccess, "Call failed");
    }

    
    modifier onlyOwner {
        if(msg.sender != i_owner){
            revert NotOwner();
        }
        //require(msg.sender == i_owner, "Sender is not the owner!");
        _;
    }

    receive() external payable {
        fund();
    }  

    fallback() external payable{
        fund();
    }
    //What happens if someone sends this contract ETH without calling the fund function
 }

Hi, I'm having trouble with remix and an error, can someone help me?