code: public function deleteByPrimaryKey($primaryKeyValue, ?string $returnField = null): ?string
      {
          // make sure role exists and is deletable
          if (null === $role = $this->getObjectById((int) $primaryKeyValue)) {
              throw new Exceptions\QueryResultsNotFoundException("Role not found: id $primaryKeyValue");
          }
  
          if (!$role->isDeletable((int) $primaryKeyValue)) {
              throw new Exceptions\UnallowedActionException("Role in use: id $primaryKeyValue");
          }
  
          return parent::deleteByPrimaryKey($primaryKeyValue, $returnField);
      }
docs: override for validation