```
function _mica_studies_population_delete($population) {
  $population_wrapper = entity_metadata_wrapper('node', $population->nid);
  watchdog('mica', 'Delete cascade for %population', array('%population' => $population_wrapper->title->value()), WATCHDOG_DEBUG);
  foreach ($population_wrapper->field_pop_dce->getIterator() as $dce_wrapper) {
    $nb_dce_pops = count($dce_wrapper->field_dce_population->value());
    if ($nb_dce_pops === 0) {
      watchdog('mica', 'Delete cascade DCE %dce', array('%dce' => $dce_wrapper->title->value()), WATCHDOG_DEBUG);
      $dce_wrapper->delete();
    }
  }
}
```