How to use the seleniumbase.fixtures.page_utils.is_valid_url function in seleniumbase

if not proxy_string:
            return None
    valid = False
    val_ip = re.match(
        r'^\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}:\d+$', proxy_string)
    if not val_ip:
        if proxy_string.startswith('http://'):
            proxy_string = proxy_string.split('http://')[1]
        elif proxy_string.startswith('https://'):
            proxy_string = proxy_string.split('https://')[1]
        elif '://' in proxy_string:
            proxy_string = proxy_string.split('://')[1]
        chunks = proxy_string.split(':')
        if len(chunks) == 2:
            if re.match(r'^\d+$', chunks[1]):
                if page_utils.is_valid_url('http://' + proxy_string):
                    valid = True
    else:
        proxy_string = val_ip.group()
        valid = True
    if not valid:
        display_proxy_warning(proxy_string)
        proxy_string = None
    return proxy_string

def generate_referral(self, start_page, destination_page):
        """ This method opens the start_page, creates a referral link there,
            and clicks on that link, which goes to the destination_page.
            (This generates real traffic for testing analytics software.) """
        if not page_utils.is_valid_url(destination_page):
            raise Exception(
                "Exception: destination_page {%s} is not a valid URL!"
                % destination_page)
        if start_page:
            if not page_utils.is_valid_url(start_page):
                raise Exception(
                    "Exception: start_page {%s} is not a valid URL! "
                    "(Use an empty string or None to start from current page.)"
                    % start_page)
            self.open(start_page)
            time.sleep(0.08)
        referral_link = ('''<a href="%s" class="analytics referral test">'''
                         '''Magic Link Button</a>''' % destination_page)
        self.execute_script(
            '''document.body.innerHTML = \"%s\"''' % referral_link)
        time.sleep(0.1)
        self.click("a.analytics.referral.test")  # Clicks the generated button
        time.sleep(0.15)
        try:

def generate_referral_chain(self, pages):
        """ Use this method to chain the action of creating button links on
            one website page that will take you to the next page.
            (When you want to create a referral to a website for traffic
            generation without increasing the bounce rate, you'll want to visit
            at least one additional page on that site with a button click.) """
        if not type(pages) is tuple and not type(pages) is list:
            raise Exception(
                "Exception: Expecting a list of website pages for chaining!")
        if len(pages) < 2:
            raise Exception(
                "Exception: At least two website pages required for chaining!")
        for page in pages:
            # Find out if any of the web pages are invalid before continuing
            if not page_utils.is_valid_url(page):
                raise Exception(
                    "Exception: Website page {%s} is not a valid URL!" % page)
        for page in pages:
            self.generate_referral(None, page)

def generate_referral(self, start_page, destination_page):
        """ This method opens the start_page, creates a referral link there,
            and clicks on that link, which goes to the destination_page.
            (This generates real traffic for testing analytics software.) """
        if not page_utils.is_valid_url(destination_page):
            raise Exception(
                "Exception: destination_page {%s} is not a valid URL!"
                % destination_page)
        if start_page:
            if not page_utils.is_valid_url(start_page):
                raise Exception(
                    "Exception: start_page {%s} is not a valid URL! "
                    "(Use an empty string or None to start from current page.)"
                    % start_page)
            self.open(start_page)
            time.sleep(0.08)
        referral_link = ('''<a href="%s" class="analytics referral test">'''
                         '''Magic Link Button</a>''' % destination_page)
        self.execute_script(

self.wait_for_ready_state_complete()
                time.sleep(0.05)
                element = self.wait_for_link_text_visible(
                    link_text, timeout=timeout)
                element.click()
        except Exception:
            found_css = False
            text_id = self.get_link_attribute(link_text, "id", False)
            if text_id:
                link_css = '[id="%s"]' % link_text
                found_css = True

            if not found_css:
                href = self.__get_href_from_link_text(link_text, False)
                if href:
                    if href.startswith('/') or page_utils.is_valid_url(href):
                        link_css = '[href="%s"]' % href
                        found_css = True

            if not found_css:
                ngclick = self.get_link_attribute(link_text, "ng-click", False)
                if ngclick:
                    link_css = '[ng-click="%s"]' % ngclick
                    found_css = True

            if not found_css:
                onclick = self.get_link_attribute(link_text, "onclick", False)
                if onclick:
                    link_css = '[onclick="%s"]' % onclick
                    found_css = True

            success = False