def process_file(self,filename=None, format=None):
        """
        Parse a file into an ontology object, using rdflib
        """
        rdfgraph = rdflib.Graph()
        if format is None:
            if filename.endswith(".ttl"):
                format='turtle'
            elif filename.endswith(".rdf"):
                format='xml'
        rdfgraph.parse(filename, format=format)
        return self.process_rdfgraph(rdfgraph)
Parse a file into an ontology object, using rdflib