generic
    type Index is (<>);
    type Counter is (<>);
package Bag_Package is
    procedure Empty(B : in out Bag);
    procedure Add(B : in out Bag; I : in Index);
    procedure Remove(B : in out Bag; I : in Index);
    function Has_Any(B: in Bag; I : in Index) return Boolean;
private
    type Bag is array(Index range <>) of Counter;
end Bag_Package;