bornhack-website/program/apps.py

from django.apps import AppConfig
from django.db.models.signals import m2m_changed, pre_save
from .signal_handlers import check_speaker_event_camp_consistency, check_speaker_camp_change

class ProgramConfig(AppConfig):
    name = 'program'

    def ready(self):
        from .models import Speaker
        m2m_changed.connect(check_speaker_event_camp_consistency, sender=Speaker.events.through)
        pre_save.connect(check_speaker_camp_change, sender=Speaker)