#' @param x A valid track object class name, or the object itself, in which #' case the class is derived directly from it. #' @param GdObject Object of `GdObject-class`. #' @param value Value to be set. #' @param from,to Numeric scalar, giving the range of genomic coordinates to #' limit the tracks in. Note that `to` cannot be larger than `from.` #' @param i Numeric scalar, index to subset. #' @param j Numeric scalar, index to subset. Ignored. #' @param f `factor` in the sense that `as.factor(f)` defines the grouping, #' @param sort `logical`. #' @param drop `logical`, indicating if levels that do not occur should be dropped (if `f` is a factor). #' @param use.defaults `logical`. #' @param ... Additional arguments. #' @param .Object .Object #' @param range range #' @param chromosome chromosome #' @param genome genome