import time
from selenium import webdriver
from selenium.webdriver.support.ui import WebDriverWait
starttime=time.time()
browser=webdriver.Firefox(executable_path='\somepath\chromedriver.exe')
browser.get("http://patft.uspto.gov/netacgi/nph-Parser?patentnumber=3,930,293")
wait = WebDriverWait(browser, 5)
wait.until(lambda driver: browser.current_url !=patent )
url=browser.current_url
r = requests.get(url)
soup = BeautifulSoup(r.text, 'lxml')

for tag in soup.find_all(text=re.compile('Current U.S. Class:')):
    table=tag.findParent('table')
            result = table.find('tr').text
            browser.close()
            print(result)    #Current U.S. Class: 29/428
            print(time.time()-starttime)