interface AggregatorInterface {
    event AnswerUpdated(int256 indexed current, uint256 indexed roundId, uint256 timestamp);
    event NewRound(uint256 indexed roundId, address indexed startedBy, uint256 startedAt);

    function latestAnswer() external view returns (int256);
    function latestTimestamp() external view returns (uint256);
    function latestRound() external view returns (uint256);
    function getAnswer(uint256 roundId) external view returns (int256);
    function getTimestamp(uint256 roundId) external view returns (uint256);

    // post-Historic

    function decimals() external view returns (uint8);
    function getRoundData(uint256 _roundId)
      external
      returns (
        uint256 roundId,
        int256 answer,
        uint256 startedAt,
        uint256 updatedAt,
        uint256 answeredInRound
      );
    function latestRoundData()
      external
      returns (
        uint256 roundId,
        int256 answer,
        uint256 startedAt,
        uint256 updatedAt,
        uint256 answeredInRound
      );
}
function decimals() external view returns (uint8);

// post-Historic