aave-protocol-v2/contracts/flashloan/interfaces/IFlashLoanReceiver.sol

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

/**
 * @title IFlashLoanReceiver interface
 * @notice Interface for the Aave fee IFlashLoanReceiver.
 * @author Aave
 * @dev implement this interface to develop a flashloan-compatible flashLoanReceiver contract
 **/
interface IFlashLoanReceiver {
  function executeOperation(
    address reserve,
    uint256 amount,
    uint256 fee,
    bytes calldata params
  ) external;
}