Hi everyone, I'm new to llamaindex. I'm trying to run the IngestionPipeline code here https://docs.llamaindex.ai/en/stable/module_guides/loading/ingestion_pipeline/. The only thing I changed is the OpenAIEmbedding model to the HuggingfaceEmbedding model. However, the index instantiation failed (empty index). I check the nodes in the vector store vector_store.get_nodes() and the nodes' embeddings are all None. What could be the issue? I tried searching for this issue in github and google but no luck so far, any help's appreciated!