type
  list<T> = class
    procedure Add(a: T);
    begin
    assert(a.Equals(5));
    assert(a.ToString()='5');
    end;
    
    procedure Add2(a:T);virtual;
    begin
      
    end;
  end;
  
  My = class(list<integer>)
  procedure Add2(a: integer);override;
  begin
    assert(a.Equals(3));
  end;
  end;
  
 begin
   var m := new My;
   m.Add(5);
   m.Add2(3);
 end.