Special new data type for no-default. Not often needed by the end-user, mainly internal.
NoDefault: R6 factory.NO_DEF: R6 Singleton object for type, used in Param.is_nodefault(): Is an object of type 'no default'?
Special new data type for no-default. Not often needed by the end-user, mainly internal.
NoDefault: R6 factory.
NO_DEF: R6 Singleton object for type, used in Param.
is_nodefault(): Is an object of type 'no default'?