aave-protocol-v2/contracts/interfaces/ILendingRateOracle.sol

// SPDX-License-Identifier: agpl-3.0
pragma solidity ^0.6.8;

/**
 * @title ILendingRateOracle interface
 * @notice Interface for the Aave borrow rate oracle. Provides the average market borrow rate to be used as a base for the stable borrow rate calculations
 **/

interface ILendingRateOracle {
  /**
    @dev returns the market borrow rate in ray
    **/
  function getMarketBorrowRate(address _asset) external view returns (uint256);

  /**
    @dev sets the market borrow rate. Rate value must be in ray
    **/
  function setMarketBorrowRate(address _asset, uint256 _rate) external;
}