Revert "removed get_knowledge_graph"

lightrag/kg/oracle_impl.py

@@ -8,6 +8,7 @@ from typing import Any, Union, final
 import numpy as np
 import configparser
 
+from lightrag.types import KnowledgeGraph
 
 from ..base import (
     BaseGraphStorage,
@@ -669,6 +670,11 @@ class OracleGraphStorage(BaseGraphStorage):
     async def delete_node(self, node_id: str) -> None:
         raise NotImplementedError
 
+    async def get_knowledge_graph(
+        self, node_label: str, max_depth: int = 5
+    ) -> KnowledgeGraph:
+        raise NotImplementedError
+
 
 N_T = {
     NameSpace.KV_STORE_FULL_DOCS: "LIGHTRAG_DOC_FULL",