code: def columns(self):
          
          from .column import Column
  
          if self.url is None or self.post_num == 0:
              return
          soup = BeautifulSoup(self._session.get(self.url + 'posts').text)
          column_list = soup.find('div', class_='column-list')
          column_tags = column_list.find_all('div', class_='item')
          for column_tag in column_tags:
              name = column_tag['title']
              url = column_tag['data-href']
              numbers = column_tag.find('span', class_='des').text.split('•')
              follower_num = int(re_get_number.match(numbers[0]).group(1))
              if len(numbers) == 1:
                  post_num = 0
              else:
                  post_num = int(
                      re_get_number.match(numbers[1]).group(1))
              yield Column(url, name, follower_num, post_num,
                           session=self._session)
docs: 获取用户专栏.
  
          :return: 用户专栏，返回生成器
          :rtype: Column.Iterable