how to add to an href in python using beauiful soup

I have a script that scrapes a web site and tests all the links in it ha it finds. My issue is that when a come across a link wih a double forward slash (like //us.cnn.com), my script fails.

Here is the code my script fails on:

elif "//" in link.get('href'):
    link = "http:" + str(link)
    print("tested link is: " + link)
    driver = webdriver.Chrome(
        '/home/ironmantis7x/PycharmProjects/WebScrapper/chromedriver')
    #driver.get(link)
    #driver.get(str(link))
    driver.get(link.get('href'))

what I am trying to do is when it comes across a link that has "//" (double slashes), i just want to send that link with http: added to it so selenium opens that complete link (http://cnn.com/us for example).

How can I accomplish this correctly?

Here is the complete script in case I is needed for reference.

from bs4 import BeautifulSoup
from selenium import webdriver
import requests
import sys
import time
from datetime import date
from datetime import datetime
import datetime

# chrome browser control options
options = webdriver.ChromeOptions()
options.add_argument('headless')
# options.add_argument('--ignore-certificate-errors')
# options.add_argument("--test-type")
options.binary_location = "/usr/bin/google-chrome"  # <--- needed actual path to chrome browser
# hard set path to chromedriver in project
# driver = webdriver.Chrome('/home/ironmantis7x/Documents/BSSLLC/projects/PycharmProjects/WebScrapper/chromedriver')

# system time for time/date stamping
now_time = datetime.datetime.now().strftime('%Y-%m-%d %H:%M:%S')

# fetching url to test
url = raw_input("Enter a website to extract the URL's from: ")

r = requests.get("http://" + url)

data = r.text

# soup = BeautifulSoup(data)
soup = BeautifulSoup(data, 'html.parser')

validURL = 0
validChildURL = 0
invalidURL = 0

for link in soup.find_all('a'):
    if "http" in link.get('href'):
        driver = webdriver.Chrome(
            '/home/ironmantis7x/PycharmProjects/WebScrapper/chromedriver')
        driver.get(link.get('href'))
        print(driver.title)
        with open('valid_link_2.txt', 'a') as f:
            print >> f, 'link:', link.get('href')
            print(link.get('href'))
            driver.get(link.get('href'))
            driver.quit()
            validURL = validURL + 1
    elif "https" in link.get('href'):
        driver = webdriver.Chrome(
            '/home/ironmantis7x/PycharmProjects/WebScrapper/chromedriver')
        driver.get(link.get('href'))
        print(driver.title)
        with open('valid_link_2.txt', 'a') as f:
            print >> f, 'link:', link.get('href')
            print(link.get('href'))
            driver.get(link.get('href'))
            driver.quit()
            validURL = validURL + 1
    elif "//" in link.get('href'):
        link = "http:" + str(link)
        print("tested link is: " + link)
        driver = webdriver.Chrome(
            '/home/ironmantis7x/PycharmProjects/WebScrapper/chromedriver')
        driver.get(link.get('href'))
        print(driver.title)
        with open('valid_link.txt', 'a') as f:
            print >> f, 'link:', link.get('href')
            print(link.get('href'))
            driver.get(link.get('href'))
            driver.quit()
            validURL = validURL + 1

    else:
        print(link.get('href') + " is an invalid link")
        with open('invalid_link.txt', 'a') as f:
            print >> f, link.get('href')
            print(link.get('href'))
            driver = webdriver.Chrome('/home/ironmantis7x/PycharmProjects/WebScrapper/chromedriver',
                                      chrome_options=options)
            driver.quit()
            invalidURL = invalidURL + 1