langchain/tools/playwright/navigate_back.py/NavigateBackTool/_run
class NavigateBackTool:    def _run(self, run_manager: Optional[CallbackManagerForToolRun] = None) -> str:
        """Use the tool."""
        if self.sync_browser is None:
            raise ValueError(f"Synchronous browser not provided to {self.name}")
        page = get_current_page(self.sync_browser)
        response = page.go_back()

        if response:
            return (
                f"Navigated back to the previous page with URL '{response.url}'."
                f" Status code {response.status}"
            )
        else:
            return "Unable to navigate back; no previous page in the history"