feat: event

contracts/ATM.sol

@@ -6,16 +6,17 @@ import "./Bank.sol";
 
 contract ATM is BaseContract{
 	Bank bank;
+	event Withdraw(address from, uint amount, uint balance );
 	constructor(address bank_addr) {
 		bank = Bank(payable(bank_addr));
 	}
 
 	function withdraw(uint amount) public {
+		require(amount<=0.1 ether, "You cannot withdraw more than 0.1 ether");
 		if(address(this).balance <= 0.1 ether) {
 			bank.withdraw(0.5 ether);
 		}
-		require(amount<=0.1 ether, "You request amount cannot bigger than 0.1 ether");
-		require(amount<=address(this).balance, "This ATM doesn't have enough ETH to withdraw");
 		payable(msg.sender).transfer(amount);
+		emit Withdraw(msg.sender, amount, address(this).balance);
 	}
 }

contracts/Bank.sol

@@ -4,7 +4,10 @@ pragma solidity >=0.4.22 <0.9.0;
 import "./BaseContract.sol";
 
 contract Bank is BaseContract{
-	address[] private atms;
+	address[] public atms;
+	event NoMoney(address from, uint amount, uint balance);
+	event Withdraw(address from, uint amount, uint balance);
+	event AddATM(address atm);
 	constructor() {}
 
 	modifier onlyATM() {
@@ -21,10 +24,15 @@ contract Bank is BaseContract{
 
 	function addATM(address atm) public onlyOwner {
 		atms.push(atm);
+		emit AddATM(atm);
 	}
 
 	function withdraw(uint amount) public onlyATM {
-		require(amount<=address(this).balance, "Bank doesn't have enough money to withdraw.");
+		if(amount<=address(this).balance){
+			emit NoMoney(msg.sender, amount, address(this).balance);
+			revert("Bank doesn't have enough money to withdraw");
+		}
 		payable(msg.sender).transfer(amount);
+		emit Withdraw(msg.sender, amount, address(this).balance);
 	}
 }