Fix the mangling issue on several VectorStores child classes. (#8274)

- Description: Fix mangling issue affecting a couple of VectorStore
classes including Redis.
  - Issue: https://github.com/langchain-ai/langchain/issues/8185
  - @rlancemartin 
  
This is a simple issue but I lack of some context in the original
implementation.
My changes perhaps are not the definitive fix but to start a quick
discussion.

@hinthornw Tagging you since one of your changes introduced this
[here.](c38965fcba)

libs/langchain/langchain/vectorstores/base.py

@@ -446,7 +446,7 @@ class VectorStore(ABC):
         """Return VectorStore initialized from texts and embeddings."""
         raise NotImplementedError
 
-    def __get_retriever_tags(self) -> List[str]:
+    def _get_retriever_tags(self) -> List[str]:
         """Get tags for retriever."""
         tags = [self.__class__.__name__]
         if self.embeddings:
@@ -455,7 +455,7 @@ class VectorStore(ABC):
 
     def as_retriever(self, **kwargs: Any) -> VectorStoreRetriever:
         tags = kwargs.pop("tags", None) or []
-        tags.extend(self.__get_retriever_tags())
+        tags.extend(self._get_retriever_tags())
         return VectorStoreRetriever(vectorstore=self, **kwargs, tags=tags)
 
 

libs/langchain/langchain/vectorstores/redis.py

@@ -607,7 +607,7 @@ class Redis(VectorStore):
 
     def as_retriever(self, **kwargs: Any) -> RedisVectorStoreRetriever:
         tags = kwargs.pop("tags", None) or []
-        tags.extend(self.__get_retriever_tags())
+        tags.extend(self._get_retriever_tags())
         return RedisVectorStoreRetriever(vectorstore=self, **kwargs, tags=tags)
 
 

libs/langchain/langchain/vectorstores/singlestoredb.py

@@ -446,7 +446,7 @@ class SingleStoreDB(VectorStore):
 
     def as_retriever(self, **kwargs: Any) -> SingleStoreDBRetriever:
         tags = kwargs.pop("tags", None) or []
-        tags.extend(self.__get_retriever_tags())
+        tags.extend(self._get_retriever_tags())
         return SingleStoreDBRetriever(vectorstore=self, **kwargs, tags=tags)
 
 

libs/langchain/langchain/vectorstores/vectara.py

@@ -409,7 +409,7 @@ class Vectara(VectorStore):
 
     def as_retriever(self, **kwargs: Any) -> VectaraRetriever:
         tags = kwargs.pop("tags", None) or []
-        tags.extend(self.__get_retriever_tags())
+        tags.extend(self._get_retriever_tags())
         return VectaraRetriever(vectorstore=self, **kwargs, tags=tags)