def METHOD_NAME(nested_list_of_objects: list) -> list:
    """Returns unique objects in a possibly nested (one level) list of objects.
    Preserves the original order in which unique objects first occurred.
    For example:
    >>> flatten_unique([1, [2, 20, 6], 10, [6, 2]])
    <<< [1, 2, 20, 6, 10]
    """
    all_objects = []
    for s in nested_list_of_objects:
        if isinstance(s, list):
            all_objects.extend(s)
        else:
            all_objects.append(s)
    return list(dict.fromkeys(all_objects).keys())