class OUDSThemeThis is a basic theme any theme must be a subclass off, or all themes must have as ancestor. A Swift class has been used so as to allow to easily override some attributes and have inheritance, without having for developers to implement all tokens. Any properties of an overridable theme should be defined so as to provide defaults values. We allow this theme to be derivated and be overriden. OUDSTheme can be seen as a kind of “abstract class” in object oriented paradigm, or theme contract. Because OUDSTheme is not a final class, its type cannot be seen as Sendable, that is the reason why this conformity is unchecked.