langchain/chains/natbot/crawler.py/Crawler/__init__
class Crawler:    def __init__(self) -> None:
        try:
            from playwright.sync_api import sync_playwright
        except ImportError:
            raise ValueError(
                "Could not import playwright python package. "
                "Please install it with `pip install playwright`."
            )
        self.browser: Browser = (
            sync_playwright().start().chromium.launch(headless=False)
        )
        self.page: Page = self.browser.new_page()
        self.page.set_viewport_size({"width": 1280, "height": 1080})
        self.page_element_buffer: Dict[int, ElementInViewPort]
        self.client: CDPSession