def diag_item_is_appl_appl4(item):
    """Returns if an item is APPL or APPL4

    :param item: item to look a
    :type item: :class:`SAPDiagItem`

    :return: whether the item is a APPL or APPL4 item
    :rtype: ``bool``
    """
    return item.item_type in [16, 18]
