contract Ownable {

    address public owner;
    address public newOwner;

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

    /**
     * @dev The Ownable constructor sets the original `owner` of the contract to the sender
     * account.
     */
    constructor() public {
        owner = msg.sender;
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        assert(msg.sender == owner);
        _;
    }

    /**
     * @dev Allows the current owner to transfer control of the contract to a newOwner.
     * @param _newOwner The address to transfer ownership to.
     */
    function transferOwnership(address _newOwner) public onlyOwner {
        assert(_newOwner != address(0));
        newOwner = _newOwner;
    }

    /**
     * @dev Accept transferOwnership.
     */
    function acceptOwnership() public {
        if (msg.sender == newOwner) {
            emit OwnershipTransferred(owner, newOwner);
            owner = newOwner;
        }
    }
}
/**
 * @title Ownable contract - base contract with an owner
 */
function transferOwnership(address _newOwner) public onlyOwner {
    assert(_newOwner != address(0));
    newOwner = _newOwner;
}

/**
 * @dev Allows the current owner to transfer control of the contract to a newOwner.
 * @param _newOwner The address to transfer ownership to.
 */