Get latest django-south migrations per app

latest.py

def get_latest_migrations():
    """
    using South' MigrationHistory, get the latest migration id per app
    using this, we can apply a --fake later on to get back the previous
    state
    """
    from south.models import MigrationHistory
    from django.db.models.aggregates import Max
    latest = MigrationHistory.objects.values('app_name').annotate(latest=Max('applied'))
    migrations = {}
    for l in latest:
        m = MigrationHistory.objects.filter(app_name=l['app_name']).filter(applied=l['latest'])
        mid = m[0].migration.split('_')[0]
        migrations[l['app_name']] = mid
    return migrations