raise ValueError(f"page.goto() returned None for url {url}")
                    text = await self.evaluator.evaluate_async(page, browser, response)
                    metadata = {"source": url}
                    docs.append(Document(page_content=text, metadata=metadata))
                except Exception as e:
                    if self.continue_on_failure:
                        logger.error(
                            f"Error fetching or processing {url}, exception: {e}"
                        )
                    else:
                        raise e
            await browser.close()
        return docs