contract PriceOracle {
    /// @notice Indicator that this is a PriceOracle contract (for inspection)
    bool public constant isPriceOracle = true;

    /**
      * @notice Get the underlying price of a bToken asset
      * @param bToken The bToken to get the underlying price of
      * @return The underlying asset price mantissa (scaled by 1e18).
      *  Zero means the price is unavailable.
      */
    function getUnderlyingPrice(BToken bToken) external view returns (uint);
}
function getUnderlyingPrice(BToken bToken) external view returns (uint);
/**
 * @notice Get the underlying price of a bToken asset
 * @param bToken The bToken to get the underlying price of
 * @return The underlying asset price mantissa (scaled by 1e18).
 *  Zero means the price is unavailable.
 */