There is a examples to create a custom validation rules using flexfields information

Summary:

Hi, we try to create a custom validation rules in subscription management using page composer, owr requisites is validate a flexfield field, any one can help me with an examples de custom validations using a flexfield?

Content (please ensure you mask any confidential information):

try
{
def subscriptionProducts = products;
List objectNameList = new ArrayList();
List severityList = new ArrayList();
List messageList = new ArrayList();
while (subscriptionProducts.hasNext())
{
def product = subscriptionProducts.next();
if (product.attribute1 == null) -- here, I want to use a flexfield
{
objectNameList.add(product.getAttribute('ProductName'));
severityList.add("error");
messageList.add("O produto" + product.LineNumber + "está com a inscrição municipal em branco, verifique a informação no flexfield.");