Member "getNumber" not found or not visible after argument-dependent lookup in uint256

Question

I was trying to check something I saw in the tutorial on the simpler example. In the tutorial it was:
using My_PriceConverter for uint256;
I tried to check it using simple contract and library
MyContract:

import "./MyLibrary.sol";

contract MyContract {
    using MyLibrary for uint256;
    uint256 public myUint;

    function setMyUint(uint256 _myUint) public {
        myUint = _myUint.getNumber();
    }
}

MyLibrary:

// SPDX-License-Identifier: UNLICENSED
pragma solidity ^0.8.9;

library MyLibrary {
    function getNumber() public pure returns (uint256) {
        return 123;
    }
}

I don't know why it's possible to use My_PriceConverter but I get error like that

Answer 1

using MyLibrary for uint256;
uint256 public myUint;

_myUint.getNumber() == MyLibrary.getNumber(_myUint)

using syntactic sugar: https://medium.com/coinmonks/soliditys-using-keyword-c05c18aaa088