[
  {
    "weight": 1,
    "value": {
      "template": "the_vault:vault/rooms/challenge/dragon1",
      "palettes": ["the_vault:dragon/base", "the_vault:dragon/room1"]
    }
  },
  {
    "weight": 0,
    "value": {
      "template": "the_vault:vault/rooms/challenge/dragon2",
      "palettes": ["the_vault:dragon/base", "the_vault:dragon/room2"]
    }
  }
]