code: def follower_num(self):
          
          if self.url is None:
              return 0
          else:
              number = int(self.soup.find(
                  'div', class_='zm-profile-side-following zg-clear').find_all(
                  'a')[1].strong.text)
              return number
docs: 获取追随者数量，就是关注此人的人数.
  
          :return: 追随者数量
          :rtype: int