User can add poolbalance without using depositTokens functions

e.g) transfer, tranferFrom,

That’s all!

function flashLoan(uint256 borrowAmount) external nonReentrant {
    require(borrowAmount > 0, "Must borrow at least one token");

    uint256 balanceBefore = damnValuableToken.balanceOf(address(this));
    require(balanceBefore >= borrowAmount, "Not enough tokens in pool");

    // Ensured by the protocol via the `depositTokens` function
    **// @audit-issue**
    ***assert(poolBalance == balanceBefore);***
    // assert(poolBalance == damnValuableToken.balanceOf(address(this));

    damnValuableToken.transfer(msg.sender, borrowAmount);

    IReceiver(msg.sender).receiveTokens(
      address(damnValuableToken),
      borrowAmount
    );

    uint256 balanceAfter = damnValuableToken.balanceOf(address(this));
    require(balanceAfter >= balanceBefore, "Flash loan hasn't been paid back");
  }