A dictionary stores key: value pairs. A key such as "item" identifies a field instead of an index. card["item"] reads it; card["qty"] = 9 updates it. Missing keys raise KeyError; card.get("aisle", "unknown") supplies a fallback.
This is an editable worked demo. Edit main.py, press Run to compare the result, then Submit to check your small change. The next lesson transfers the idea to a different setting.
Change item to read the name, not the quantity. Run should print paper; then Submit.
card["item"] into item.