{
  "condition": "minecraft:entity_properties",
  "entity": "this",
  "predicate": {
    "type": "minecraft:player",
    "equipment": {
      "mainhand": {
        "item": "minecraft:written_book",
        "nbt": "{author:\"The Mayor\",ench:[{id:0,lvl:0}]}"
      }
    }
  }
}