gdal_polygonize.py --version (return code: 0)
GDAL 2.2.1, released 2017/06/23
gdal_polygonize.py -HELP (return code: 1)
gdal_polygonize [-8] [-nomask] [-mask filename] raster_file [-b band|mask]
[-q] [-f ogr_format] out_file [layer] [fieldname]