protected function removeWorstPerformersFromPopulation()
 {
     $worstPerformerIdentifiers = $this->scoreManager->getWorstPerformersUniqueIdentifiers($this->citizensCountToReplacePerGeneration);
     foreach ($worstPerformerIdentifiers as $identifier) {
         $this->population->removeCitizenByUniqueIdentifier($identifier);
     }
 }