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

    //  @dev Throws if called by any account other than the owner. 
    modifier onlyOwner() 
    {
        require(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
    {
        if (newOwner != address(0)) 
        {
            owner = newOwner;
        }
    }
}
function Ownable() public 
{
    owner = msg.sender;
}

//  @dev The Ownable constructor sets the original `owner` of the contract to the sender
//  account.