function totalSupply() external view returns (uint256);

function balanceOf(address owner) external view returns (uint256);

function allowance(address owner, address spender) external view returns (uint256);

function approve(address spender, uint256 wad) external returns (bool);

function transfer(address to, uint256 wad) external returns (bool);

function transferFrom(address from, address to, uint256 wad) external returns (bool);

function deposit() external payable;

function withdraw(uint256 wad) external;

event Approval(address indexed owner, address indexed spender, uint256 value);

event Transfer(address indexed from, address indexed to, uint256 value);

event Deposit(address indexed dst, uint256 wad);

event Withdrawal(address indexed src, uint256 wad);