UnstructuredFileLoader
https://python.langchain.com/docs/integrations/document_loaders/unstructured_file
https://github.com/langchain-ai/langchain/blob/v0.0.353/libs/community/langchain_community/document_loaders/unstructured.py
Example
https://github.com/langchain-ai/langchain/blob/v0.0.353/libs/community/langchain_community/document_loaders/unstructured.py#L146-L153
デフォルトではmode="single"
unstructured.partition.auto.partitionの結果の要素が
"\n\n"
でjoinされた文字列にまとまる
Partitioning (unstructured)