code: protected function createConfigurationDefinition()
      {
          return new FixerConfigurationResolver([
              (new FixerOptionBuilder('closure_function_spacing', 'Spacing to use before open parenthesis for closures.'))
                  ->setDefault(self::SPACING_ONE)
                  ->setAllowedValues($this->supportedSpacings)
                  ->getOption(),
          ]);
      }
docs: {@inheritdoc}