Function map_binary

pub fn map_binary<F>(a: Expr, b: Expr, f: F, output_type: GetOutput) -> Expr
where
    F: 'static + Fn(Column, Column) -> PolarsResult<Option<Column>> + Send + Sync,

Apply a closure on the two columns that are evaluated from Expr a and Expr b.

The closure takes two arguments, each a Series. output_type must be the output dtype of the resulting Series.