       true
 
   """
+  @doc since: "1.3.0"
   @spec leap_year?(year) :: boolean()
   @impl true
   def leap_year?(year) when is_integer(year) do

      "02:02:02.000002"

  """
  @spec time_to_string(
          Calendar.hour(),
          Calendar.minute(),

      "02:02:02"

  """
  @doc since: "1.5.0"
  @spec time_to_string(
          Calendar.hour(),
          Calendar.minute(),
