langchain/document_loaders/parsers/pdf.py/PDFMinerParser/lazy_parse
class PDFMinerParser:    def lazy_parse(self, blob: Blob) -> Iterator[Document]:
        """Lazily parse the blob."""
        from pdfminer.high_level import extract_text

        with blob.as_bytes_io() as pdf_file_obj:
            text = extract_text(pdf_file_obj)
            metadata = {"source": blob.source}
            yield Document(page_content=text, metadata=metadata)