CloudFormation | Snippet with uninformed example(s)

Please, I am interested in learning more about Rules - AWS CloudFormation and, when analyzing the official documentation, in the examples section available, there is no demo snippet. Could someone tell me what the code is so I can use it as a reference?

Reference link: https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/rules-section-structure.html#template-constraint-rules-example