如何在Ejabberd elixir模块中注册IQ处理程序？

import :iq
import XMPP.Stanza
import Ejabberd

def handle_iq(iq, _from, state) do
  case iq do
    %IQ{type: :set, sub_el: sub_el} ->
      handle_set_iq(iq, sub_el, _from, state)
    %IQ{type: :get, sub_el: sub_el} ->
      handle_get_iq(iq, sub_el, _from, state)
    _ ->
      {:error, "Unsupported IQ type"}
  end
end

defmodule MyModule do
  def start_link(_type, _args) do
    Ejabberd.start_link(__MODULE__, :ok, name: __MODULE__)
  end

  def init(:ok) do
    IQ.register_iq_handler(:all, &handle_iq/3)
    {:ok, []}
  end
end

modules:
  - {mod, MyModule}