'Parent Invoice Id', 'comment' => 'Comment', ]; /** * Validate data * * @param \Magento\Sales\Model\Order\Invoice\Comment $comment * @return array */ public function validate(Comment $comment) { $errors = []; $commentData = $comment->getData(); foreach ($this->required as $code => $label) { if (!$comment->hasData($code)) { $errors[$code] = sprintf('"%s" is required. Enter and try again.', $label); } elseif (empty($commentData[$code])) { $errors[$code] = sprintf('%s can not be empty', $label); } } return $errors; } }