     case :beam_lib.chunks(file, [:attributes]) do
       {:ok, {module, [attributes: attributes]}} ->
         callback.(module, attributes)
-       _ ->
-         nil
+
+      _ ->
+        nil
     end
   end
 

    do_defimpl(protocol, :lists.keysort(1, opts))
  end

  defp do_defimpl(protocol, [do: block, for: for]) when is_list(for) do
    for f <- for, do: do_defimpl(protocol, [do: block, for: f])
  end

  defp do_defimpl(protocol, [do: block, for: for]) do
    # Unquote the implementation just later
    # when all variables will already be injected
    # into the module body.

  def __ensure_defimpl__(protocol, for, env) do
    if Protocol.consolidated?(protocol) do
      message =
        "the #{inspect(protocol)} protocol has already been consolidated" <>
          ", an implementation for #{inspect(for)} has no effect"

      :elixir_errors.warn(env.line, env.file, message)
    end

    :ok
  end

