code: @Override
      public NutMap pay_transfers(String key, WxPayTransfers wxPayTransfers, File file, String password) {
          String url = payBase + "/mmpaymkttransfers/promotion/transfers";
          Map<String, Object> params = Lang.obj2map(wxPayTransfers);
          return this.postPay(url, key, params, file, password);
      }
docs: 企业向个人付款
  
  @param key
  商户KEY
  @param wxPayTransfers
  付款内容
  @param file
  证书文件
  @param password
  证书密码
  @return