pub trait IterFromColumn<'a, T> {
// Required method
fn create_iter(
dataframe: &'a DataFrame,
column_name: &'a str,
) -> PolarsResult<Box<dyn Iterator<Item = Option<T>> + 'a>>
where Self: Sized;
// Provided method
fn get_value(
_polars_value: Option<T>,
_column_name: &'a str,
) -> PolarsResult<Self>
where Self: Sized { ... }
}