langchain/document_loaders/confluence.py/ConfluenceLoader/process_pdf
class ConfluenceLoader:    def process_pdf(self, link: str) -> str:
        try:
            import pytesseract  # noqa: F401
            from pdf2image import convert_from_bytes  # noqa: F401
        except ImportError:
            raise ImportError(
                "`pytesseract` or `pdf2image` package not found, "
                "please run `pip install pytesseract pdf2image`"
            )

        response = self.confluence.request(path=link, absolute=True)
        text = ""

        if (
            response.status_code != 200
            or response.content == b""
            or response.content is None
        ):
            return text
        try:
            images = convert_from_bytes(response.content)
        except ValueError:
            return text

        for i, image in enumerate(images):
            image_text = pytesseract.image_to_string(image)
            text += f"Page {i + 1}:\n{image_text}\n\n"

        return text