langchain/document_loaders/blob_loaders/schema.py/Blob/as_bytes_io
class Blob:    def as_bytes_io(self) -> Generator[Union[BytesIO, BufferedReader], None, None]:
        """Read data as a byte stream."""
        if isinstance(self.data, bytes):
            yield BytesIO(self.data)
        elif self.data is None and self.path:
            with open(str(self.path), "rb") as f:
                yield f
        else:
            raise NotImplementedError(f"Unable to convert blob {self}")