langchain/document_loaders/base.py/BaseLoader/load_and_split
class BaseLoader:    def load_and_split(
        self, text_splitter: Optional[TextSplitter] = None
    ) -> List[Document]:
        """Load documents and split into chunks."""
        if text_splitter is None:
            _text_splitter: TextSplitter = RecursiveCharacterTextSplitter()
        else:
            _text_splitter = text_splitter
        docs = self.load()
        return _text_splitter.split_documents(docs)