Function map_model::make::initial::geometry::deadend

fn deadend(
    driving_side: DrivingSide, 
    roads: &mut BTreeMap<OriginalRoad, Road>, 
    i: NodeID, 
    lines: &Vec<(OriginalRoad, Line, PolyLine, PolyLine)>
) -> Result<(Polygon, Vec<(String, Polygon)>), String>