def extract_favicon(bs4):
    """Extracting favicon url from BeautifulSoup object

    :param bs4: `BeautifulSoup`
    :return: `list` List of favicon urls
    """

    favicon = []

    selectors = [
        'link[rel="icon"]',
        'link[rel="Icon"]',
        'link[rel="ICON"]',
        'link[rel^="shortcut"]',
        'link[rel^="Shortcut"]',
        'link[rel^="SHORTCUT"]'
    ]

    for selector in selectors:

        icons = bs4.select(selector)

        if icons:

            for icon in icons:

                if icon.has_attr('href'):

                    favicon.append(icon['href'])

    return favicon
Extracting favicon url from BeautifulSoup object

    :param bs4: `BeautifulSoup`
    :return: `list` List of favicon urls