code: def _prepare_ingest(self):
          
  
          # see also commentary on DigitalObject.DUMMY_URIREF
          self.replace_uri(self.obj.DUMMY_URIREF, self.obj.uriref)
docs: If the RDF datastream refers to the object by the default dummy
          uriref then we need to replace that dummy reference with a real one
          before we ingest the object.