langchain/document_loaders/pdf.py/MathpixPDFLoader/load
class MathpixPDFLoader:    def load(self) -> List[Document]:
        pdf_id = self.send_pdf()
        contents = self.get_processed_pdf(pdf_id)
        if self.should_clean_pdf:
            contents = self.clean_pdf(contents)
        metadata = {"source": self.source, "file_path": self.source}
        return [Document(page_content=contents, metadata=metadata)]