Function polars_lazy::dsl::arg_sort_by  
pub fn arg_sort_by<E>(by: E, sort_options: SortMultipleOptions) -> ExprAvailable on crate feature 
range only.Expand description
Find the indexes that would sort these series in order of appearance.
That means that the first Series will be used to determine the ordering
until duplicates are found. Once duplicates are found, the next Series will
be used and so on.