langchain/indexes/vectorstore.py/VectorstoreIndexCreator/from_documents
class VectorstoreIndexCreator:    def from_documents(self, documents: List[Document]) -> VectorStoreIndexWrapper:
        """Create a vectorstore index from documents."""
        sub_docs = self.text_splitter.split_documents(documents)
        vectorstore = self.vectorstore_cls.from_documents(
            sub_docs, self.embedding, **self.vectorstore_kwargs
        )
        return VectorStoreIndexWrapper(vectorstore=vectorstore)