请给我一个2024年12月的日历，要求输出一个30行4列的表格，每行代表一周，每列代表一个月，每个单元格显示从1号到7号。输出形式必须为json格式，并且包含完整的2024年12月的日历数据。
user
```json
{
  "year": 2024,
  "month": 12,
  "weeks": [
    {
      "week": 1,
      "days": [1, 2, 3, 4, 5, 6, 7]
    },
    {
      "week": 2,
      "days": [8, 9, 10, 11, 12, 13, 14]
    },
    {
      "week": 3,
      "days": [15, 16, 17, 18, 19, 20, 21]
    },
    {
      "week": 4,
      "days": [22, 23, 24, 25, 26, 27, 28]
    },
    {
      "week": 5,
      "days": [29, 30, 31, null, null, null, null]
    }
  ]
}
```
assistant