def _elem_set_attrs(obj, parent, to_str):
    """
    :param obj: Container instance gives attributes of XML Element
    :param parent: XML ElementTree parent node object
    :param to_str: Callable to convert value to string or None
    :param options: Keyword options, see :func:`container_to_etree`

    :return: None but parent will be modified
    """
    for attr, val in anyconfig.compat.iteritems(obj):
        parent.set(attr, to_str(val))
:param obj: Container instance gives attributes of XML Element
    :param parent: XML ElementTree parent node object
    :param to_str: Callable to convert value to string or None
    :param options: Keyword options, see :func:`container_to_etree`

    :return: None but parent will be modified