请用json格式给出建国以来中国历任总理的姓名和国籍，以数组形式返回数据，每个总理是一个对象。数组必须包含name、nationality两个字段
user
{
  "presidents": [
    {
      "name": "周恩来",
      "nationality": "中国"
    },
    {
      "name": "华国锋",
      "nationality": "中国"
    },
    {
      "name": "赵紫阳",
      "nationality": "中国"
    },
    {
      "name": "李鹏",
      "nationality": "中国"
    },
    {
      "name": "朱镕基",
      "nationality": "中国"
    },
    {
      "name": "温家宝",
      "nationality": "中国"
    },
    {
      "name": "李克强",
      "nationality": "中国"
    }
  ]
}
assistant