anchor.diff:        expect(printer('ab'), 'ab');
         expect(printer('abc'), 'bc');
         expect(printer('abcd'), 'cd');
  +      expect(printer.toString(), startsWith('TakeLastPrinter'));
       });
       test('skip', () {
         final printer = standardString.skip(2);
  
positive.code:       expect(() => Printer<String>.wrap(standardInt), throwsArgumentError);
        expect(() => Printer<String>.wrap(num.parse), throwsArgumentError);
        expect(() => Printer<String>.wrap(12), throwsArgumentError);
      });
    });
    group('object', () {
  
negative.code:       expect(printer('ab'), 'ab');
        expect(printer('abc'), 'ab');
        expect(printer('abcd'), 'ab');
        expect(printer.toString(), startsWith('TakePrinter'));
      });
      test('takeLast', () {
        final printer = standardString.takeLast(2);
  