langchain/tools/playwright/current_page.py/CurrentWebPageTool/_run
class CurrentWebPageTool:    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)
        return str(page.url)