code: def get_quotation_kline(self, symbol, period, limit=None, _async=False):
          
          params = {}
          path = '/quotation/market/history/kline'
          params['symbol'] = symbol
          params['period'] = period
          if limit:
              params['limit'] = limit
  
          return api_key_get(params, path, _async=_async)
docs: 获取etf净值
          :param symbol: etf名称
          :param period: K线类型
          :param limit: 获取数量
          :param _async:
          :return: