Problem with Web View Pages tutorial

Web View Pages

I following the tutorial to make the changes to the Article doctype, but I cannot see the ‘See on Website’ on the top left of the Article form. How to view the web page view of the article?


Edit:
I open localhost:8000/articles InPrivate window, I can see a list of articles. Buit when I click on the article link, I got Error Code: 500 with the error below:

Traceback (most recent call last):
  File "apps/frappe/frappe/website/serve.py", line 20, in get_response
    return renderer_instance.render()
           ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "apps/frappe/frappe/website/page_renderers/document_page.py", line 41, in render
    html = self.get_html()
           ^^^^^^^^^^^^^^^
  File "apps/frappe/frappe/website/utils.py", line 534, in cache_html_decorator
    html = func(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^
  File "apps/frappe/frappe/website/page_renderers/document_page.py", line 50, in get_html
    self.update_context()
  File "apps/frappe/frappe/website/page_renderers/document_page.py", line 57, in update_context
    self.context.update(self.context.doc.get_page_info())
                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: 'Article' object has no attribute 'get_page_info'