def flatten(iterable):
    result = []
    for item in iterable:
        if isinstance(item, (list, tuple)):
            # is the element is a list or a tuple, we call 'flatten' recursively /// Ak je prvok zoznamom alebo konvojom, voláme funkciu flatten rekurzívne
            result.extend(flatten(item))
        elif item is not None:
            # pridame prvok len vtedy, ak nie je None /// add an element only if it is not None
            result.append(item)
    return result