   end
 
   @impl true
-  def datetime_to_string(year, month, day,
-                         hour, minute, second, microsecond,
-                         _time_zone, zone_abbr, _utc_offset, _std_offset) do
+  def datetime_to_string(
+        year,
+        month,
+        day,
+        hour,
+        minute,
+        second,
+        microsecond,
+        _time_zone,
+        zone_abbr,
+        _utc_offset,
+        _std_offset
+      ) do
     "#{year}-#{month}-#{day}" <>
       Calendar.ISO.time_to_string(hour, minute, second, microsecond) <> " #{zone_abbr} (HE)"
   end
 
   @impl true
-  defdelegate time_to_string(hour, minute, second, microsecond), to: Calendar.ISO
+  defdelegate(time_to_string(hour, minute, second, microsecond), to: Calendar.ISO)
 
   @impl true
   def day_rollover_relative_to_midnight_utc(), do: {0, 1}

  def naive_datetime_from_iso_days(entry) do
    {year, month, day, hour, minute, second, microsecond} =
      Calendar.ISO.naive_datetime_from_iso_days(entry)
    {year + 10000, month, day, hour, minute, second, microsecond}
  end

  @impl true
  def naive_datetime_to_iso_days(year, month, day, hour, minute, second, microsecond) do
    Calendar.ISO.naive_datetime_to_iso_days(year - 10000, month, day, hour, minute, second, microsecond)
  end

  @impl true
  defdelegate time_from_day_fraction(day_fraction), to: Calendar.ISO

  @impl true
  defdelegate time_to_day_fraction(hour, minute, second, microsecond), to: Calendar.ISO

  @impl true
  defdelegate leap_year?(year), to: Calendar.ISO

  @impl true
  defdelegate days_in_month(year, month), to: Calendar.ISO

  @impl true
  defdelegate day_of_week(year, month, day), to: Calendar.ISO

  @impl true
  def valid_date?(year, month, day) do

  end

  @impl true
  defdelegate(valid_time?(hour, minute, second, microsecond), to: Calendar.ISO)
end
