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;
    }
}