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

// SPDX-License-Identifier: agpl-3.0
pragma solidity 0.6.12;

interface ICreditDelegationToken {
  event BorrowAllowanceDelegated(
    address indexed fromUser,
    address indexed toUser,
    address asset,
    uint256 amount
  );

  /**
   * @dev delegates borrowing power to a user on the specific debt token
   * @param delegatee the address receiving the delegated borrowing power
   * @param amount the maximum amount being delegated. Delegation will still
   * respect the liquidation constraints (even if delegated, a delegatee cannot
   * force a delegator HF to go below 1)
   **/
  function approveDelegation(address delegatee, uint256 amount) external;

  /**
   * @dev returns the borrow allowance of the user
   * @param fromUser The user to giving allowance
   * @param toUser The user to give allowance to
   * @return the current allowance of toUser
   **/
  function borrowAllowance(address fromUser, address toUser) external view returns (uint256);
}