def learners(self, event):
        return Person.objects.filter(task__event=event,
                                     task__role=self.learner)
Check the configuration of Apache for errors.
dataset/ETHPy150Open swcarpentry/amy/workshops/management/commands/trainings_completion_rates.py/Command.learners--crossover with--dataset/ETHPy150Open letsencrypt/letsencrypt/certbot-apache/certbot_apache/configurator.py/ApacheConfigurator.config_test