Marking Objects as Defunct
When a function is removed from R it should be replaced by a function
.Defunct(new, package = NULL, msg)
character string: A suggestion for a replacement function.
character string: The package to be used when suggesting where the defunct function might be listed.
character string: A message to be printed, if missing a default message is used.
.Defunct is called from defunct functions. Functions should be
help("pkg-defunct") for an appropriate
base (with the alias added to the respective Rd
base-defunct and so on which list the defunct functions
in the packages.