This is the advanced follow-up to Flatten a 2D Array. Practice that challenge first. Here lists may contain more lists at any depth. In C++ and C#, use the NestedValue type in the starter code. Read kind first: 0 means skip this entry, 1 means append value, and 2 means visit items recursively.

Turn a nested list into a flat list of integers. Read from left to right; whenever you reach another list, read its contents before continuing. Ignore null values (shown as None in examples) and empty lists. Preserve repeated integers and their order.

Python receives ordinary nested lists containing integers and None. C++ and C# receive a list of NestedValue objects supplied by the starter: kind 0 means null, kind 1 means integer in value, and kind 2 means a list in items. Only the field selected by kind matters. Return a plain integer list in every language.

Implement flatten_arbitrarily_nested_list(values).

Input

values: A list whose entries can be integers, null, or further lists.

Output

Return the integers in depth-first, left-to-right order. Return an empty list when there are no integers.

อินพุต:
values = [
    1,
    [
        2,
        None,
        [3]
    ],
    [],
    4
]

ผลลัพธ์ที่คาดหวัง:
[1, 2, 3, 4]

อินพุต:
values = [
    None,
    [],
    [None]
]

ผลลัพธ์ที่คาดหวัง:
[]