WeChat.CustomMessage.send_menu

You're seeing just the function send_menu, go back to WeChat.CustomMessage module for more information.
Link to this function

send_menu(client, openid, map)

Specs

客服消息接口 - 发送菜单消息 - 官方文档

Example

WeChat.CustomMessage.send_menu(client, openid, {
  head_content: "您对本次服务是否满意呢?",
  list: [
    {
      id: "101",
      content: "满意"
    },
    {
      id: "102",
      content: "不满意"
    }
  ],
  tail_content: "欢迎再次光临"
})