consider use a string to indicate card finish for Sealed.Content.Card

[kodawah]

    card:
    - set: one
      name: Phyrexian Arena
      number: 283
      foil: true

Instead of a boolean foil field there should be an option to select the finish property as reported by mtgjson/scryfall, that is a string for nonfoil, foil and etched - this would make it more consistent with the style used elsewhere, in particular in Decks