"EmptyMethodsList" are generated during
method selection to indicate failed search (forcing backtracking).
Other classes described here are used internally in method dispatch.
All these are for internal use.## class described below
"EmptyMethodsList"### Other, virtual classes used in method dispatch
"OptionalMethods"
"PossibleMethod"
argument:"name" the argument
names being selected on.sublist:"list" (unused, and
perhaps to be dropped in a later version.) "EmptyMethodsList" in the
signature.MethodsListSelect (deprecated since R version
3.2.0) uses the objects;
class is formally defunct since R 3.2.0.