Looks like deck_id references a persisted model: https://github.com/crobertsbmw/deckofcards/blob/master/deck/models.py#L23 https://github.com/crobertsbmw/deckof

Looks like deck_id references a persisted model: https://github.com/crobertsbmw/deckofcards/blob/master/deck/models.py#L23 https://github.com/crobertsbmw/deckofcards/blob/master/deck/... The model stores the state of the deck, including things like order and remaining cards and how many "decks" of 52 cards are in play.