fixes issue #19 (we should do this in the 2.4.x branch too)
fixes issue #19 (we should do this in the 2.4.x branch too)

ssssam/rdflib,dbs/rdflib,armandobs14/rdflib,yingerj/rdflib,RDFLib/rdflib,ssssam/rdflib,avorio/rdflib,marma/rdflib,ssssam/rdflib,yingerj/rdflib,armandobs14/rdflib,armandobs14/rdflib,yingerj/rdflib,marma/rdflib,dbs/rdflib,RDFLib/rdflib,dbs/rdflib,avorio/rdflib,RDFLib/rdflib,dbs/rdflib,RDFLib/rdflib,marma/rdflib,avorio/rdflib,avorio/rdflib,yingerj/rdflib,marma/rdflib,armandobs14/rdflib,ssssam/rdflib