code: protected function createConfigurationDefinition()
      {
          $that = $this;
  
          return new FixerConfigurationResolverRootless('tokens', [
              (new FixerOptionBuilder('tokens', 'List of tokens to fix.'))
                  ->setAllowedTypes(['array'])
                  ->setAllowedValues([new AllowedValueSubset(self::$availableTokens)])
                  ->setNormalizer(static function (Options $options, $tokens) use ($that) {
                      foreach ($tokens as &$token) {
                          if ('useTrait' === $token) {
                              $message = "Token \"useTrait\" in option \"tokens\" for rule \"{$that->getName()}\" is deprecated and will be removed in 3.0, use \"use_trait\" instead.";
  
                              if (getenv('PHP_CS_FIXER_FUTURE_MODE')) {
                                  throw new InvalidConfigurationException("{$message} This check was performed as `PHP_CS_FIXER_FUTURE_MODE` env var is set.");
                              }
  
                              @trigger_error($message, E_USER_DEPRECATED);
                              $token = 'use_trait';
  
                              break;
                          }
                      }
  
                      return $tokens;
                  })
                  ->setDefault(['extra'])
                  ->getOption(),
          ], $this->getName());
      }
docs: {@inheritdoc}