lua – How to align balls to a player in Vavio

How can you target an opponent in Vavio and then shoot a ball? Here is the code I tried:

LevelSpawnData / spawnData-L0.json

{
"spawn": [
    {
      "time": 3.2,
      "leave": 12.8,
      "pattern": "Test/aim.lua",
      "movement": "Test/move.lua",
      "model": "circle",
      "material": "red",
      "x": 0.5
    }
  ]
}

Patterns / BulletSpawning / Test / aim.lua

bullet = pattern.NewBullet ()
bullet.speed = 3
bullet.angle = ??? - Do you want to adjust this to the player
pattern.SpawnBullet (ball)