IList<DisplayUnitFormat> GetPredefinedProjectUnitFormats( 
   UnitFormatType unitFormat
)

//Must be on the QueuedTask.Run()

var unit_formats = Enum.GetValues(typeof(UnitFormatType))
                      .OfType<UnitFormatType>().ToList();
System.Diagnostics.Debug.WriteLine("All available units\r\n");

foreach (var unit_format in unit_formats)
{
  var units = DisplayUnitFormats.Instance.GetPredefinedProjectUnitFormats(unit_format);
  System.Diagnostics.Debug.WriteLine(unit_format.ToString());

  foreach (var display_unit_format in units)
  {
    var line = $"{display_unit_format.DisplayName}, {display_unit_format.UnitCode}";
    System.Diagnostics.Debug.WriteLine(line);
  }
  System.Diagnostics.Debug.WriteLine("");
}

//Must be on the QueuedTask.Run()

//UnitFormatType.Angular, UnitFormatType.Area, UnitFormatType.Distance, 
//UnitFormatType.Direction, UnitFormatType.Location

//Get the full list of all available location units
var all_units = DisplayUnitFormats.Instance.GetPredefinedProjectUnitFormats(
                                                      UnitFormatType.Location);
//keep units with an even factory code
var list_units = all_units.Where(du => du.UnitCode % 2 == 0).ToList();

//set them as the new location unit collection. A new default is not being specified...
DisplayUnitFormats.Instance.SetProjectUnitFormats(list_units);

//set them as the new location unit collection along with a new default
DisplayUnitFormats.Instance.SetProjectUnitFormats(
                                        list_units, list_units.First());

//Note: UnitFormatType.Page, UnitFormatType.Symbol2D, UnitFormatType.Symbol3D
//cannot be set.