## Multiple Stocks

Now we should consider multiple tickers, so the input for an operation will also contain a new information called "ticker" that will be an identifier of which asset you're selling. The profit calculation (through weighted-average price) and quantity validation (if implemented) on selling should also consider the ticker.

When you sell at a loss, you should use the loss from one ticker toward any other ticker.

`````````
Input #1
[{"operation":"buy", "unit-cost":10, "quantity": 10000, "ticker":"AAPL"},
{"operation":"buy", "unit-cost":15, "quantity": 10000, "ticker":"MANU"}, {"operation":"sell", "unit-cost":20, "quantity": 10000, "ticker":"AAPL"},
{"operation":"sell", "unit-cost":30, "quantity": 10000, "ticker":"MANU"}]

Output #1
[{"tax":0}, {"tax":0}, {"tax":20000}, {"tax":30000}]

Input #2

[{"operation":"buy", "unit-cost":10, "quantity": 10000, "ticker":"AAPL"},
{"operation":"buy", "unit-cost":15, "quantity": 10000, "ticker":"MANU"}, 
{"operation":"sell", "unit-cost":5, "quantity": 10000, "ticker":"AAPL"},
{"operation":"sell", "unit-cost":30, "quantity": 10000, "ticker":"MANU"}]

Output #2
[{"tax":0}, {"tax":0}, {"tax":0}, {"tax":20000}]

Input #3
[{"operation":"buy", "unit-cost":10, "quantity": 10000, "ticker":"AAPL"},
{"operation":"buy", "unit-cost":15, "quantity": 10000, "ticker":"MANU"},
{"operation":"sell", "unit-cost":30, "quantity": 10000, "ticker":"MANU"},
{"operation":"sell", "unit-cost":5, "quantity": 10000, "ticker":"AAPL"}]

Output #3
[{"tax":0}, {"tax":0}, {"tax":30000}, {"tax":0}]
`````````