Get instance of an existing Hologres store.This method will return the instance of the store without inserting any new embeddings
from_existing_index(
cls: Type[Hologres],
embedding: Embeddings,
ndims: int = ADA_TOKEN_COUNT,
table_name: str = _LANGCHAIN_DEFAULT_TABLE_NAME,
pre_delete_table: bool = False,
**kwargs: Any = {}
) -> Hologres