Parsing MeSH RDF with Owlready2 returns empty ontology
After loading MeSH (ftp://ftp.nlm.nih.gov/online/mesh/rdf/mesh.nt.gz) with Owlready2 I obtain an ontology object that has no classes, individuals, or properties (i.e., onto.classes(), onto.individuals(), etc., return empty collections). There are no errors or warnings thrown during loading. I'm using Owlready2 v0.31 and Python 3.9.5.
For comparison, when loading MeSH with the OWL API (and Protege), it parses appropriately and I can browse the class hierarchy and obtain MeSH terms.
Any help or hints to fix the issue are much appreciated.