Revert "Cleanup of code"

lightrag/kg/mongo_impl.py

@@ -601,6 +601,24 @@ class MongoGraphStorage(BaseGraphStorage):
     # -------------------------------------------------------------------------
     #
 
+    async def get_all_labels(self) -> list[str]:
+        """
+        Get all existing node _id in the database
+        Returns:
+            [id1, id2, ...]  # Alphabetically sorted id list
+        """
+        # Use MongoDB's distinct and aggregation to get all unique labels
+        pipeline = [
+            {"$group": {"_id": "$_id"}},  # Group by _id
+            {"$sort": {"_id": 1}},  # Sort alphabetically
+        ]
+
+        cursor = self.collection.aggregate(pipeline)
+        labels = []
+        async for doc in cursor:
+            labels.append(doc["_id"])
+        return labels
+
     async def get_knowledge_graph(
         self, node_label: str, max_depth: int = 5
     ) -> KnowledgeGraph: