internal static new string ToString()
{
Contracts.Assert(_invariantNameToHexMap.All(x => !CharacterUtils.HasSpaces(x.Key)));
var colorText = string.Join(", ", _invariantNameToHexMap.Select(x => x.Key + ":#" + string.Format("{0:X6}", x.Value)));
return("%c[" + colorText + "]");
}