code: public function error($message)
      {
          if ($message) {
              if (is_int($message) && isset($this->errorList[$message])) {
                  /*
                   * If the message is of type integer use a predefine
                   * error message
                   */
                  $errorMessage = $this->errorList[$message];
                  $this->report("Error[{$message}]: {$errorMessage}"); //Report The error
              } else {
                  $errorMessage = $message;
                  $this->report("Error: {$errorMessage}"); //Report The error
              }
  
              $errors = &$this->getErrors();
              $errors[] = $errorMessage;
          }
  
          return $this;
      }
docs: Log an error
  
  @param string|int $message - An error message to log or the index of a predefined error
  
  @return $this