The third lesson, why can't I run it, I'm a little bit confused about the case

[3200459199]

Follow the video step by step knock, I do not know why return that line shows an error, because of the case problem?

Here is the code, please solve

// SPDX-License-Identifier: MIT;
pragma solidity ^0.8.0;

import "./simplestorage.sol";

contract StorageFactory {

    SimpleStorage[] public simpleStorageArray;

    function createSimplestorageContract() public {
        SimpleStorage simpleStorage = new SimpleStorage();
        simpleStorageArray.push(simpleStorage);
    }

    function sfStore(uint256 _simpleStorageIndex,uint256 _simpleStorageNumber) public {
        SimpleStorage simpleStorage = simpleStorageArray[_simpleStorageIndex];
        simpleStorage.store(_simpleStorageNumber);
    }

    function sfGet(uint256 _simpleStorageIndex) public view returns(uint256){
        SimpleStorage simpleStorage = simpleStorageArray[_simpleStorageIndex];
        return simpleStorage.retrieve();
    }
}

[alymurtazamemon]

@3200459199 Hover over the error and show me that

[3200459199]

Thank you for your reply, this is the error reported

[alymurtazamemon]

@3200459199 Make sure the retrieve function is public

[3200459199]

Thank you, I got it, no call to the introduced function, thank you