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 deposit()
    public
    payable
{}

/// @dev Buys tokens with Ether, exchanging them 1:1.