code: protected function createConfigurationDefinition()
      {
          return new FixerConfigurationResolver([
              (new FixerOptionBuilder('sort_algorithm', 'The sorting algorithm to apply.'))
                  ->setAllowedValues(['alpha', 'none'])
                  ->setDefault('alpha')
                  ->getOption(),
              (new FixerOptionBuilder('null_adjustment', 'Forces the position of `null` (overrides `sort_algorithm`).'))
                  ->setAllowedValues(['always_first', 'always_last', 'none'])
                  ->setDefault('always_first')
                  ->getOption(),
          ]);
      }
docs: {@inheritdoc}