pragma solidity ^0.8.4;

contract Ownable {

    address public owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    modifier onlyOwner {
        require(isOwner(msg.sender));
        _;
    }

    constructor() public {
        owner = msg.sender;
    }

    function transferOwnership(address newOwner) public onlyOwner {
        emit OwnershipTransferred(owner, newOwner);
        owner = newOwner;
    }

    function isOwner(address addr) public view returns (bool) {
        return owner == addr;
    }
}