'This method is called with the source of each downloaded :term:`HTML` file, before
any of the cleanup attributes like remove_tags, keep_only_tags are
applied. Note that preprocess_regexps will have already been applied.
It is meant to allow the recipe to skip ad pages. If the soup represents
an ad page, return the HTML of the real page. Otherwise return
None.
`soup`: A `BeautifulSoup <https://www.crummy.com/software/BeautifulSoup/bs3/documentation.html>`_
instance containing the downloaded :term:`HTML`.'

def skip_ad_pages(self, soup):

    return None
