code: def etf_swap_in(self, etf_name, amount, _async=False):
          
  
          params = {}
          path = '/etf/swap/in'
          params['etf_name'] = etf_name
          params['amount'] = amount
  
          return api_key_post(params, path,  _async=_async)
docs: 换入etf
          :param etf_name: etf基金名称
          :param amount:   数量
          :param _async:
          :return: