Bug in addCard method example

[Kevin LeStarge]

This example doesn't work:
creditCardType.addCard(visa.type, visa);
The addCard method only seems to work with one object as a param. Like this:
creditCardType.addCard(visa);
*visa is an object returned and altered from the getTypeInfo method.

[Blade Barringer]

Would you like to update the docs?

[Kevin LeStarge]

Sure! Give me a couple hours and I'll submit a pull request.