def METHOD_NAME(self, orm):
    # Adding field 'Maintenance.started_at'
    db.add_column(u'maintenance_maintenance', 'started_at',
                  self.gf('django.db.models.fields.DateTimeField')(
                      null=True),
                  keep_default=False)
    # Adding field 'Maintenance.finished_at'
    db.add_column(u'maintenance_maintenance', 'finished_at',
                  self.gf('django.db.models.fields.DateTimeField')(
                      null=True),
                  keep_default=False)