enchantment to duplicate the experience received from mobs

I'm trying to create an enchantment that duplicates the experience mobs receive when killed. I used the minecraft:mob_experience effect but it's not working. On a technical level, enchanting should make more experience_orbs appear. Unfortunately I can't get it to work when I test it.
{
  "description": "Essence Extractor",
  "exclusive_set": [
    "minecraft:looting",
    "minecraft:mending"
  ],
  "supported_items": "#minecraft:enchantable/sword",
  "weight": 1,
  "max_level": 2,
  "min_cost": {
    "base": 20,
    "per_level_above_first": 14
  },
  "max_cost": {
    "base": 70,
    "per_level_above_first": 14
  },
  "anvil_cost": 6,
  "slots": [
    "hand"
  ],
  "effects": {
    "minecraft:mob_experience": [
      {
        "effect": {
          "type": "minecraft:multiply",
          "factor": {
            "type": "minecraft:linear",
            "base": 1,
            "per_level_above_first": 1
          }
        },
        "requirements": {
          "condition": "minecraft:entity_properties",
          "entity": "this",
          "predicate": {
            "type": "minecraft:player"
          }
        }
      }
    ]
  }
}

I also tried removing the condition but it still doesn't work.