code: public function configure(array $configuration = null)
      {
          parent::configure($configuration);
  
          if ('echo' === $this->configuration['use']) {
              $this->candidateTokenType = T_PRINT;
              $this->callBack = 'fixPrintToEcho';
          } else {
              $this->candidateTokenType = T_ECHO;
              $this->callBack = 'fixEchoToPrint';
          }
      }
docs: {@inheritdoc}