Function lineplot_add_y 

pub fn lineplot_add_y<Y: ToString>(
    plot: &mut Plot<GridCanvas>,
    y: &[Y],
    options: LineplotSeriesOptions,
) -> Result<(), LineplotError>

Adds a y-only line series to an existing plot with implicit x = 1..=n.

Errors

Returns LineplotError::EmptySeries for empty input and LineplotError::InvalidNumericValue when parsing fails.