Function map_model::make::initial::geometry::generalized_trim_back

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