{
  "type": "advancement_reward",
  "pools": [
    {
      "rolls": 0,
      "entries": [
        {
          "type": "tag",
          "name": "irons_spellbooks:patchouli_drop",
          "expand": true
        }
      ],
      "functions": [
        {
          "function": "set_nbt",
          "tag": "{\"patchouli:book\": \"irons_spellbooks:iss_guide_book\"}"
        }
      ]
    }
  ]
}