Function polars::prelude::fold_exprs

pub fn fold_exprs<F, E>(acc: Expr, f: F, exprs: E) -> Expr where
    F: 'static + Fn(Series, Series) -> Result<Series, PolarsError> + Send + Sync + Clone,
    E: AsRef<[Expr]>, 

Accumulate over multiple columns horizontally / row wise.