docs: def find_comment_by_id(self, comment_id):
          """doc: http://open.youku.com/docs/doc?id=32
          """
          url = 'https://openapi.youku.com/v2/comments/show.json'
          params = {
              'client_id': self.client_id,
              'comment_id': comment_id
          }
          r = requests.get(url, params=params)
          check_error(r)
          return r.json()