Creating shapefile using GDAL OGR? Script runs but does not create the files

This script runs but does not create the shapefile files. It works, however, if I were to replace the driver for GeoJSON and create a GeoJSON file. Context: I’m working through Chris Garrard’s "Geoprocessing with Python".

from osgeo import ogr
shp_fn = r'C:UsersimperDesktopNew foldershp_test.shp'
shp_driver = ogr.GetDriverByName('ESRI Shapefile')
shp_ds = shp_driver.CreateDataSource(shp_fn)
if shp_ds is None:
    sys.Exit('Could not create {0}.'.format(shp_fn))