with_blogpost_7.ex

def join_game(user_id, game_id) do
  with {:user, {:ok, user}} <- get_user(user_id), 
       {:game, {:ok, game}} <- get_game(game_id),
       # Etc...
end

defp get_user(id) do
  {:user, Users.get(id)}
end

defp get_game(id) do
  {:game, Games.get(id)}
end