classRepresentation
  to describe a particular class.  Mostly a utility function, but you can
  call it to create a class definition without assigning it, as
  setClass would do.
makeClassRepresentation(name, slots=list(), superClasses=character(), prototype=NULL, package, validity, access, version, sealed, virtual=NA, where)setClass, but without the unnamed arguments for
    superClasses if any.prototype.getPackageName.validObject, and the discussion of validity methods in
    the reference.setClass.Chambers, John M. (1998) Programming with Data Springer (For the original S4 version.)
setClass