'Add a URL path to a HTML document with links to kernel files.
:param url: URL path to a HTML file with links to kernel files
(can be either an absolute URL or one relative to self.prefix)
:param pattern: regex pattern to filter kernel files links out of
all othe links found in the HTML document'

def add_url(self, url, pattern):

    if ((url[(-1):] != '/') and (not self._extension_pattern.match(url))):
        url = (url + '/')
    self.urls.append((url, re.compile(pattern)))
