contract owned
{
    address payable internal owner;
    address payable internal newOwner;
    address payable internal signer;

    event OwnershipTransferred(address indexed _from, address indexed _to);

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

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


    modifier onlySigner {
        require(msg.sender == signer, 'caller must be signer');
        _;
    }


    function changeSigner(address payable _signer) public onlyOwner {
        signer = _signer;
    }

    function transferOwnership(address payable  _newOwner) public onlyOwner {
        newOwner = _newOwner;
    }

    //the reason for this flow is to protect owners from sending ownership to unintended address due to human error
    function acceptOwnership() public {
        require(msg.sender == newOwner);
        emit OwnershipTransferred(owner, newOwner);
        owner = newOwner;
        newOwner = address(0);
    }
}
function acceptOwnership() public {
        require(msg.sender == newOwner);
        emit OwnershipTransferred(owner, newOwner);
        owner = newOwner;
        newOwner = address(0);
    }
//the reason for this flow is to protect owners from sending ownership to unintended address due to human error