# Place a symbol at the end of the first axis number (text)
blg_frmt_symbol_append <- function (x, first = TRUE) {
    fun <- function(labels) {
        pos <- if (first) which(!is.na(labels))[1L] else rev(which(!is.na(labels)))[1L]
        labels[pos] <- paste(labels[pos], x)
        labels
    }
}