code: public function checkFragment($fragment = null)
      {
          if ($fragment === null) {
              $fragment = $this->fragment;
          }
  
          if (strlen($fragment) == 0) {
              return true;
          }
  
          $pattern = "/^" . $this->regex["uric"] . "*$/";
          $status = @preg_match($pattern, $fragment);
  
          if ($status === false) {
              throw new Ts3Exception("URI fragment validation failed");
          }
  
          return ($status == 1);
      }
docs: Returns TRUE if the fragment string is valid.
  
  @param  string $fragment
  @throws Ts3Exception
  @return boolean