interface ISynth {
    function proxy() external view returns (address);

    // Mutative functions
    function transferAndSettle(address to, uint256 value)
        external
        returns (bool);

    function transferFromAndSettle(
        address from,
        address to,
        uint256 value
    ) external returns (bool);
}
function transferAndSettle(address to, uint256 value)
    external
    returns (bool);

// Mutative functions