Chap9, recipe 4, install problem

[cocq]

Hi,

Thank you very much for all the codes for the book.

Nevertheless, when I install the "mymodule" to test recipe4 of chap9, I have the followoing error message :

"Drupal\Core\Entity\Exception\UnsupportedEntityTypeDefinitionException: The entity type message does not have an "revision_created" entity revision metadata key. in Drupal\mymodule\Entity\Message::revisionLogBaseFieldDefinitions() (line 35 of core\lib\Drupal\Core\Entity\RevisionLogEntityTrait.php). "

How remove this error?

My drupal version is 10.1.7

Regards,