code: def flush(self):
          
          base_graph = rdflib.Graph().parse('{}/rest'.format(self.base_url))
          has_child = rdflib.URIRef(
              'http://fedora.info/definitions/v4/repository#hasChild')
          for obj in base_graph.objects(predicate=has_child):
              self.delete(str(obj))
docs: Method flushes repository, deleting all objects