code: def list_members(self, list_id=None, slug=None, owner_screen_name=None, owner_id=None):
          
          assert list_id or (slug and (owner_screen_name or owner_id))
          url = 'https://api.twitter.com/1.1/lists/members.json'
          params = {'cursor': -1}
          if list_id:
              params['list_id'] = list_id
          else:
              params['slug'] = slug
              if owner_screen_name:
                  params['owner_screen_name'] = owner_screen_name
              else:
                  params['owner_id'] = owner_id
  
          while params['cursor'] != 0:
              try:
                  resp = self.get(url, params=params, allow_404=True)
              except requests.exceptions.HTTPError as e:
                  if e.response.status_code == 404:
                      log.error("no matching list")
                  raise e
  
              users = resp.json()
              for user in users['users']:
                  yield user
              params['cursor'] = users['next_cursor']
docs: Returns the members of a list.
  
          List id or (slug and (owner_screen_name or owner_id)) are required