def get_class_name(obj: object) -> str:
    """
    Get the full class name of an object.

    :param obj: A Python object.
    :return: A qualified class name.
    """
    module = obj.__class__.__module__

    if module is None or module == str.__class__.__module__:
        return obj.__class__.__name__

    return module + "." + obj.__class__.__name__