Cart class insertion question.

[eluser]mrbinky3000[/eluser]
I have a question about how the cart class works.

If I have a button on my website that uses ajax to add an item to the cart.

What happens if I press that button multiple times and call the same routine, with the same arguments, to add the same product to the cart multiple times? Does each successive call to insert() increase the quantity by one? That is my desired outcome. Or, does it insert multiple rows of the same order to the cart?