       ...>                 hour: 23, minute: 0, second: 7, microsecond: {0, 0},
       ...>                 utc_offset: -14400, std_offset: 0, time_zone: "America/Manaus"}
       iex> DateTime.convert!(dt1, Calendar.ISO)
-      %DateTime{year: 2000, month: 2, day: 29, zone_abbr: "AMT",
-                hour: 23, minute: 0, second: 7, microsecond: {0, 0},
-                utc_offset: -14400, std_offset: 0, time_zone: "America/Manaus"}
+      #DateTime<2000-02-29 23:00:07-04:00 AMT America/Manaus>
 
   """
   @spec convert!(DateTime.t, Calendar.calendar) :: DateTime.t

      iex> dt1 = %DateTime{year: 2000, month: 2, day: 29, zone_abbr: "AMT",
      ...>                 hour: 23, minute: 0, second: 7, microsecond: {0, 0},
      ...>                 utc_offset: -14400, std_offset: 0, time_zone: "America/Manaus"}
      iex> DateTime.convert(dt1, Calendar.ISO)
      {:ok, %DateTime{year: 2000, month: 2, day: 29, zone_abbr: "AMT",
                      hour: 23, minute: 0, second: 7, microsecond: {0, 0},
                      utc_offset: -14400, std_offset: 0, time_zone: "America/Manaus"}}

  """
  @spec convert(DateTime.t, Calendar.calendar) :: {:ok, DateTime.t} | {:error, atom}

  ## Examples

      iex> DateTime.from_naive!(~N[2016-05-24 13:26:08.003], "Etc/UTC")
      #DateTime<2016-05-24 13:26:08.003Z>

  """
  @spec from_naive!(non_neg_integer, :native | System.time_unit) :: DateTime.t
