WEMIX Swap & DIOS(Dollar in and out Stabilizer)

In the contract `HellowWorld` the role `initializer` has authority over the functions shown in the diagram below. Any compromise to the `initializer` account may allow the hacker to take advantage of this authority. 

The modifier `onlyWallet` has such check: ```solidity require(msg.sender == address(this), "Treasury: Only Wallet can access."); ``` , which means the `msg.sender` should be the contract itself, however, the following related functions: `addOwner()`, `removeOwner()`, `replaceOwner()` and `changeQuorum()` are not externally called in this contract, as a result, these functions could never be called.

Code commented in both Korean and English.

Performing integer division before multiplication truncates the low bits, losing the precision of calculation. ```solidity=17 uint256 invariant = reserveA * reserveB * truePriceTokenB / truePriceTokenA; ``` ```solidity=19 uint256 leftSide = Babylonian.sqrt(53200 * invariant / 53067 + reserveA * reserveA / 636804); ```

There should always be events emitted in the sensitive functions that are controlled by centralization roles.

The **require** can be used to check for conditions and throw an exception if the condition is not met. It is better to provide a string message containing details about the error that will be passed back to the caller.

`WWEMIX` implements the interface `IWWEMIX`, but does not inherit from it. ```solidity=7 contract WWEMIX is ERC20 { ``` ```solidity=6 interface IWWEMIX is IERC20 { ```

Addresses should be checked before assignment or external call to make sure they are not zero addresses. ```solidity=86 WUSDC = _WUSDC; ``` - `_WUSDC` is not zero-checked before being used. --- ```solidity=87 WEMIX$ = _WEMIX$; ``` - `_WEMIX$` is not zero-checked before being used. --- ```solidity=88 weswapFactory = _weswapFactory; ``` - `_weswapFactory` is not zero-checked before being used. --- ```solidity=90 WUSDCTreasury = _WUSDCTreasury; ``` ```solidity=91 feePool = _WUSDCTreasury; ``` - `_WUSDCTreasury` is not zero-checked before being used. --- ```solidity=92 stabilityPool = _stabilityPool; ``` - `_stabilityPool` is not zero-checked before being used. --- ```solidity=52 WUSDC = _WUSDC; ``` - `_WUSDC` is not zero-checked before being used. --- ```solidity=53 WEMIX$ = _WEMIX$; ``` - `_WEMIX$` is not zero-checked before being used. --- ```solidity=54 WUSDCTreasury = _WUSDCTreasury; ``` - `_WUSDCTreasury` is not zero-checked before being used.

Given the `_FromTokenAContractAddress` is checked whether it is one of the paired tokens, we assume a check for `_FromTokenBContractAddress` should also be added to ensure logical completeness.

The existence of `_pairAddress` should be checked to ensure `token0` and `token1` are existing.