------
## 最终结论
```python
def maximum(arr, k):
    # 验证输入
    if not isinstance(arr, list) or not all(isinstance(x, int) for x in arr):
        raise ValueError("arr must be a list of integers.")
    if not isinstance(k, int) or k < 0 or k > len(arr):
        raise ValueError("k must be a non-negative integer and less than or equal to the length of arr.")
    
    # 对数组进行排序
    arr.sort()
    
    # 提取最大k个数并返回有序列表
    return sorted(arr[-k:])
```