11 add_itemÌ16Í($artnr, $num)ÎCartÖ0
12 function: Cart :: add_item($artnr, $num)
13 fooÌ16Í($arg_1, $arg_2, ..., $arg_n)Ö0
14 function: foo($arg_1, $arg_2, ..., $arg_n)
16 variable: Cart :: items
17 remove_itemÌ16Í($artnr, $num)ÎCartÖ0
18 function: Cart :: remove_item($artnr, $num)