Mix formatter wants

    fetched_members =
      Enum.group_by(
        fetched_rooms,
        fn %Chat.Room{id: room_id} -> room_id end,
        fn %Chat.Room{members: members} ->
          Enum.map(members, fn %User{id: user_id} -> user_id end)
        end
      )

to look like this

    fetched_members =
      Enum.group_by(fetched_rooms, fn %Chat.Room{id: room_id} -> room_id end, fn %Chat.Room{
                                                                                   members:
                                                                                     members
                                                                                 } ->
        Enum.map(members, fn %User{id: user_id} -> user_id end)
      end)

Is this expected, or an improvement is possible?