\name{AdditiveUnit-class}
\docType{class}
\alias{AdditiveUnit-class}
\title{
An internal class
}
\description{
An internal class
}
\details{
This class is a super class for \code{\link{Heatmap-class}}, \code{\link{HeatmapList-class}} and \code{\link{HeatmapAnnotation-class}} classes.
It is only designed for \code{+} generic method so that above three classes can be appended to each other.
}
\examples{
# no example
NULL

}