contract KToken is StandardToken {
    address private underlying_;

    constructor(string memory name, string memory symbol, uint8 decimals, address _underlying) StandardToken(name, symbol, decimals) {
        underlying_ = _underlying;
    }

    /// @return The address of the underlying token.
    function underlying() public view returns (address) {
        return underlying_;
    }
}
function underlying() public view returns (address) {
    return underlying_;
}

/// @return The address of the underlying token.