Hi. Great work, I love too see people creating micro-services with Lambda. Lambda is an awesome tool. We process credit card payments and ran into this issue s

Hi. Great work, I love too see people creating micro-services with Lambda. Lambda is an awesome tool. We process credit card payments and ran into this issue so I just wanted to point it out to the community. With that said, the "source" object can be a "dictionary containing the customer's credit card details" so it can be miss-used. You may want to put a disclaimer in the `README.md` or maybe a `console.log` with a warning if a credit card dictionary is passed.