# assuming there are 3 elements in anIterator.
sliced_iterator = islice_extended(anIterator, -3, None, 1)
next(sliced_iterator)
next(sliced_iterator)

class IteratorWithWeakReferences:
    """
    A class that wraps an iterator and provides weak references to its elements.
    This class allows iteration over a collection of objects while maintaining
    weak references to the original objects. It can be used to track the validity
    of the objects (i.e., whether they are still alive or has been deleted).
    """
    class AnObject:
        def __init__(self, index: int):
            self.index = index

        def __str__(self):
            return f"AnObject({self.index})"

    @classmethod
    def FROM_SIZE(cls, size: int) -> IteratorWithWeakReferences:
        return cls([IteratorWithWeakReferences.AnObject(index=index) for index in range(size)])

    def __init__(self, iterable: Iterable):
        self._data = deque(element for element in iterable)
        self._weakReferences = [weakref.ref(a) for a in self._data]

    def __iter__(self) -> Iterator:
        return self

    def __next__(self) -> AnObject:
        if (len(self._data) == 0):
            raise StopIteration

        return self._data.popleft()

    def weakReferencesAliveStatePerIndex(self) -> list[bool]:
        """
        Checks the alive state of weak references of the initial iterator elements.

        Returns:
            list[bool]: A list of boolean values where each element corresponds to the alive state
            of a weak reference.
            - `True` indicates the reference is still alive
            - `False`indicates the reference has been deleted.
        """
        return [wr() is not None for wr in self._weakReferences]

    def __str__(self):
        overview = f"IteratorWithWeakReferences('initial size':{len(self._weakReferences)} 'remaining elements':{len(self._data)})\n"
        overview += str([f'[{index}]:{"Alive" if wr() else "Deleted"} ' for (index, wr) in enumerate(self._weakReferences)])
        return overview

iteratorSize = 3
iteratorwwr = IteratorWithWeakReferences.FROM_SIZE(size=iteratorSize)
islice_extended_iterator = islice_extended(iteratorwwr, 0, None, 1)
print(f"iteratorwwr state: {iteratorwwr}")

print(f"Returned element: {next(islice_extended_iterator)}")
print(f"iteratorwwr state: {iteratorwwr}")

print(f"Returned element: {next(islice_extended_iterator)}")
print(f"Returned element: {next(islice_extended_iterator)}")
print(f"iteratorwwr state: {iteratorwwr}")

iteratorSize = 3
iteratorwwr = IteratorWithWeakReferences.FROM_SIZE(size=iteratorSize)
islice_extended_iterator = islice_extended(iteratorwwr, -3, None, 1)
print(f"iteratorwwr state: {iteratorwwr}")

print(f"Returned element: {next(islice_extended_iterator)}")
print(f"iteratorwwr state: {iteratorwwr}")

print(f"Returned element: {next(islice_extended_iterator)}")
print(f"Returned element: {next(islice_extended_iterator)}")
print(f"iteratorwwr state: {iteratorwwr}")

try:
    next(islice_extended_iterator)
except StopIteration:
    print(">> encountered StopIteration as expected")
print(f"iteratorwwr state: {iteratorwwr}")