Update src/ontology_manager.py

src/ontology_manager.py

@@ -19,7 +19,8 @@ class OntologyManager:
         """
         self.ontology_path = ontology_path
         self.ontology_data = self._load_ontology()
-        self.graph = self._build_graph()
+        self.graph = nx.MultiDiGraph()
+        self._build_graph()
         
     def _load_ontology(self) -> Dict:
         """Load the ontology from the JSON file."""