The project contains two external files that are not included in Github:
roads.dbf
https://gis-bucket-aswinvk28.s3.eu-west-2.amazonaws.com/gdal_exercises/gdal_exercises/roads.dbf
roads.shp
https://gis-bucket-aswinvk28.s3.eu-west-2.amazonaws.com/gdal_exercises/gdal_exercises/roads.shp