How to use the ontospy.core.sparqlHelper.SparqlHelper function in ontospy

def load_rdf(self,
                 uri_or_path=None,
                 data=None,
                 file_obj=None,
                 rdf_format="",
                 verbose=False,
                 hide_base_schemas=True,
                 hide_implicit_types=True,
                 hide_implicit_preds=True):
        """Load an RDF source into an ontospy/rdflib graph"""
        loader = RDFLoader(verbose=verbose)
        loader.load(uri_or_path, data, file_obj, rdf_format)
        self.rdflib_graph = loader.rdflib_graph
        self.sources = loader.sources_valid
        self.sparqlHelper = SparqlHelper(self.rdflib_graph)
        self.namespaces = sorted(self.rdflib_graph.namespaces())

def __init__(self, rdfgraph, sparql_endpoint=False):
        super(SparqlHelper, self).__init__()
        self.rdflib_graph = rdfgraph
        self.sparql_endpoint = sparql_endpoint

        # Bind a few prefix, namespace pairs for easier sparql querying
        self.rdflib_graph.bind("rdf", rdflib.namespace.RDF)
        self.rdflib_graph.bind("rdfs", rdflib.namespace.RDFS)
        self.rdflib_graph.bind("owl", rdflib.namespace.OWL)
        self.rdflib_graph.bind("skos", rdflib.namespace.SKOS)
        self.rdflib_graph.bind("dc", "http://purl.org/dc/elements/1.1/")
        self.rdflib_graph.bind("vann", "http://purl.org/vocab/vann/")
        self.rdflib_graph.bind("void", "http://rdfs.org/ns/void#")
        self.rdflib_graph.bind("xsd", "http://www.w3.org/2001/XMLSchema#")
        self.rdflib_graph.bind("sh", "http://www.w3.org/ns/shacl#")

"""
        try:
            # graph = rdflib.Graph('SPARQLStore')
            # graph = rdflib.ConjunctiveGraph('SPARQLStore')
            graph = rdflib.ConjunctiveGraph('SPARQLUpdateStore')

            if credentials and type(credentials) == tuple:
                # https://github.com/RDFLib/rdflib/issues/343
                graph.store.setCredentials(credentials[0], credentials[1])
                # graph.store.setHTTPAuth('BASIC') # graph.store.setHTTPAuth('DIGEST')

            graph.open(sparql_endpoint)
            self.rdflib_graph = graph
            self.sparql_endpoint = sparql_endpoint
            self.sources = [sparql_endpoint]
            self.sparqlHelper = SparqlHelper(self.rdflib_graph, self.sparql_endpoint)
            self.namespaces = sorted(self.rdflib_graph.namespaces())
        except:
            printDebug("Error trying to connect to Endpoint.")
            raise
        # don't extract entities by default..