从多维数组中删除空维

def remove_empty_dimension(arr):
    if isinstance(arr, list):
        for i in range(len(arr)-1, -1, -1):
            if isinstance(arr[i], list):
                remove_empty_dimension(arr[i])
                if len(arr[i]) == 0:
                    arr.pop(i)
            elif arr[i] is None:
                arr.pop(i)
    return arr

arr = [1, [2, [3, None]], [], [4, []]]
result = remove_empty_dimension(arr)
print(result)