 
   """
   @doc since: "1.4.0"
-  @spec day_of_week(year, month, day) :: day_of_week
+  @spec day_of_week(year, month, day) :: day_of_week()
   @impl true
   def day_of_week(year, month, day) do
     date_to_iso_days(year, month, day)


  """
  @doc since: "1.8.0"
  @spec quarter_of_year(year, month, day) :: 1..4
  @impl true
  def quarter_of_year(year, month, day)
      when is_year(year) and is_month(month) and is_day(day) do

  @doc since: "1.5.0"
  @impl true
  @spec time_from_day_fraction(Calendar.day_fraction()) ::
          {hour(), minute(), second(), Calendar.microsecond()}
  def time_from_day_fraction({0, _}) do
    {0, 0, 0, {0, 6}}
  end
