Problem with life cycle hooks

I am a bit stumped…

I am trying to attach a life cycle hook to close flash messages automatically after 5 seconds.

I have this code:

defmodule MailManWeb.FlashLive do
  def on_mount(:default, _params, _session, socket) do
    {:cont,
     socket
     |> Phoenix.LiveView.attach_hook(:flash, :handle_params, &send_close/3)
     |> Phoenix.LiveView.attach_hook(:flash, :handle_info, &info/2)}
  end

  def send_close(_params, _uri, socket) do
    Enum.each(Phoenix.LiveView.Utils.get_flash(socket), fn {key, _msg} ->
      Process.send_after(self(), {:close_flash, key}, 5000)
    end)

    {:cont, socket}
  end

  defp info({:close_flash, key}, socket) do
    {:cont, socket |> Phoenix.LiveView.clear_flash(key)}
  end

  defp info(_, socket), do: {:cont, socket}
end

I initially had the Enum.each in the on_mount, but then it wasn’t executed when using a patch navigation.
Problem is now, it is not working on navigate navigation, I get a no function clause matching error on handle_info, it is as if the hook isn’t set.

I tried moving the attach_hook into the send_close function, but then it explodes on patch because the hook is already set.

What am I missing?