```php
function upgrade_174() {
  $this->runAllClassesInDirectory('Upgrade_174');
}
```

```php
class Upgrade_174_SetDrupalVariable implements UpgraderInterface {

  public function upgrade() {
    drush_vset('foo', 'bar');
  }

}
```

#### Directory Structure

- Upgrade_173
  - Upgrade_173_CreateOptionValue.php
- Upgrade_174
  - Upgrade_174_SetDrupalVariable.php
  - Upgrade_174_DeleteLocationType.php