// SPDX-License-Identifier: Proprietary

pragma solidity ^0.8.0;

contract Owned {
    address public contractOwner;

    event OwnershipTransferred(
        address indexed from,
        address indexed to
    );

    modifier onlyContractOwner {
        require(contractOwner == msg.sender, "Not owner");
        _;
    }

    function setContractOwner(address newContractOwner) public onlyContractOwner {
        require(newContractOwner != address(0), "0 owner disallowed");
        emit OwnershipTransferred(contractOwner, newContractOwner);
        contractOwner = newContractOwner;
    }
}