code: public function value($encoding = null)
      {
          if ($this->value !== null) {
              if ($encoding === null) {
                  return mb_convert_encoding($this->value, $this->encoding, 'UTF-8');
              } else {
                  $encoding = $this->getRealEncoding($encoding);
                  return mb_convert_encoding($this->value, $encoding, 'UTF-8');
              }
          }
      }
docs: Get the value
  
  @param  string $encoding
  @return string