title: What does error TypeError: 'NoneType' object is not iterable mean?
body: <pre><code>from bs4 import BeautifulSoup
  import requests
  import time
  
  urls = ['http://www.soku.com/search_playlist/q_python_orderby_1_limitdate_0?site=14&amp;page={}&amp;spm=a2h0k.8191403.0.00'.format(str(i)) for i in range(1,30,1)]
  
  def UUrl(urls):
  
      def Url(url):
          single_urls = []
          time.sleep(1)
          wb_data = requests.get(url)
          soup = BeautifulSoup(wb_data.text,'lxml')
          for single_urls  in soup.find_all(class_ = "album_tit"):
              single_url = (single_urls.a.get('href'))
              return single_url
              # print(single_url)
  
      for url in urls:
          Url(url)
  
  def get_url_title(urls,data = None):
      urlsss = UUrl(urls)
      for surl in urlsss:
          wb_data = requests.get(surl)
          soup = BeautifulSoup(wb_data.text,'lxml')
          urlss = soup.find_all(class_="title short-title")
          titles = soup.find_all(class_="title short-title")
  
          for t_url,title in zip(urlss,titles):
              data = {
                   'title':title.get_text(),
                   'url': (t_url.a.get('href'))
              }
              print(data)
  
  get_url_title(urls)
  </code></pre>