Function polars::frame::group_by::aggregations::_agg_helper_slice    
source ยท pub fn _agg_helper_slice<T, F>(groups: &[[u32; 2]], f: F) -> Serieswhere
    F: Fn([u32; 2]) -> Option<<T as PolarsNumericType>::Native> + Send + Sync,
    T: PolarsNumericType,
    ChunkedArray<T>: IntoSeries,Available on crate feature 
algorithm_group_by only.