#' @param entities 1-[character] string filtering the rows of the returned value, possible values are: "station" for filtering on station rows, "site" for filtering on site rows, "both" for keeping all the rows
#'
#' @return a [tibble::tibble] with all available parameters in columns and one row by time step and by station.
#' If the query returns no records then the returned value is [NULL].