contract EtherToken is Token {

    /// @dev Buys tokens with Ether, exchanging them 1:1.
    function deposit()
        public
        payable
    {}

    /// @dev Sells tokens in exchange for Ether, exchanging them 1:1.
    /// @param amount Number of tokens to sell.
    function withdraw(uint amount)
        public
    {}
}
function withdraw(uint amount)
    public
{}

/// @dev Sells tokens in exchange for Ether, exchanging them 1:1.
/// @param amount Number of tokens to sell.