#' @param filename Name of the resulting .xlsx file
#' @param ... List of dataframes to have as sheets
#' @param sheetNames List of sheet names in order of the ... argument. If left NULL (default), then the dataframe object names will be used as sheet names.
#' @param keepNames The function automatically renames the column names with \code{\link[stringr:case]{stringr::str_to_sentence()}}. Setting this to TRUE will leave your column names unaltered
#' @param overwrite Sets permissions for overwriting old files. Default is TRUE
#' @param dollarCols Vector of strings specifying the columns to save as ACCOUNTING datatypes in Excel
#' @param percentCols Vector of strings specifying the columns to save as PERCENTAGE datatypes in Excel
#' @param condCols Vector of strings specifying the columns to apply conditional coloring to in Excel
#' @param condColors Vector of length 2 or 3 that defines the colors used in conditional formatting
#' @param lowBad When TRUE (default), colors low values the first color in the vector (Red by default), if false, inverts the vector
#' @param rule Allows specification of the conditional color numeric range. Defaults to min/max of column