fix the postgres get all labels and get knowledge graph

examples/test_postgres.py

@@ -0,0 +1,51 @@
+import os
+import asyncio
+from lightrag.kg.postgres_impl import PGGraphStorage
+from lightrag.llm.ollama import ollama_embedding
+from lightrag.utils import EmbeddingFunc
+
+#########
+# Uncomment the below two lines if running in a jupyter notebook to handle the async nature of rag.insert()
+# import nest_asyncio
+# nest_asyncio.apply()
+#########
+
+WORKING_DIR = "./local_neo4jWorkDir"
+
+if not os.path.exists(WORKING_DIR):
+    os.mkdir(WORKING_DIR)
+
+# AGE
+os.environ["AGE_GRAPH_NAME"] = "dickens"
+
+os.environ["POSTGRES_HOST"] = "localhost"
+os.environ["POSTGRES_PORT"] = "15432"
+os.environ["POSTGRES_USER"] = "rag"
+os.environ["POSTGRES_PASSWORD"] = "rag"
+os.environ["POSTGRES_DATABASE"] = "rag"
+
+
+async def main():
+    graph_db = PGGraphStorage(
+        namespace="dickens",
+        embedding_func=EmbeddingFunc(
+            embedding_dim=1024,
+            max_token_size=8192,
+            func=lambda texts: ollama_embedding(
+                texts, embed_model="bge-m3", host="http://localhost:11434"
+            ),
+        ),
+        global_config={},
+    )
+    await graph_db.initialize()
+    labels = await graph_db.get_all_labels()
+    print("all labels", labels)
+
+    res = await graph_db.get_knowledge_graph("FEZZIWIG")
+    print("knowledge graphs", res)
+
+    await graph_db.finalize()
+
+
+if __name__ == "__main__":
+    asyncio.run(main())