draw the sequence diagram for the following

Question

Draw the sequence diagram for the following scenario of eBroker.

Sell Stock

1. The user enters the username and password
2. The system checks that the user is a valid user using information from the user database.
3. The user enters the stock symbol.
4. The system displays current price information for the stock.
5. The user enters sale transaction data such as number of stocks to sell and price
6. The system checks whether the user has adequate number of stocks in his account to sell.
7. The system creates a new sale transaction.
8. The system informs the stock exchange about the sale transaction.
9. The stock exchange informs the system (eBroker) when the sale is executed.
10. The system updates the user's account.
11. The system terminates the sale transaction created in step 7.

Assume the following classes: stock, sale transaction, account. You can add any other classes you deem necessary.