code: def followed_columns(self):
          
          from .column import Column
          if self.url is None:
              return
          if self.followed_column_num > 0:
              tag = self.soup.find('div', class_='zm-profile-side-columns')
              if tag is not None:
                  for a in tag.find_all('a'):
                      yield Column(a['href'], a.img['alt'],
                                   session=self._session)
              if self.followed_column_num > 7:
                  offset = 7
                  gotten_data_num = 20
                  while gotten_data_num == 20:
                      params = {
                          'hash_id': self.hash_id,
                          'limit': 20,
                          'offset': offset
                      }
                      data = {
                          'method': 'next',
                          '_xsrf': self.xsrf,
                          'params': json.dumps(params)
                      }
                      j = self._session.post(Author_Get_More_Follow_Column_URL,
                                             data=data).json()
                      gotten_data_num = len(j['msg'])
                      offset += gotten_data_num
                      for msg in map(BeautifulSoup, j['msg']):
                          name = msg.strong.text
                          url = msg.a['href']
                          post_num = int(re_get_number.match(
                              msg.span.text).group(1))
                          yield Column(url, name, post_num=post_num,
                                       session=self._session)
docs: 获取用户关注的专栏.
  
          :return: 用户关注的专栏，返回生成器
          :rtype: Column.Iterable