def formfield_for_manytomany(self, db_field, request=None, **kwargs):
        if self.salmonella_fields in db_field.name:
            try:
                kwargs['widget'] = SalmonellaMultiIdWidget(db_field.rel)
            except TypeError:  # django 1.4+
                kwargs['widget'] = SalmonellaMultiIdWidget(db_field.rel, self.admin_site)
            kwargs['help_text'] = ''
            return db_field.formfield(**kwargs)
        return super(SalmonellaMixin, self).formfield_for_manytomany(db_field,
                                                                     request,
                                                                     **kwargs)
dataset/ETHPy150Open lincolnloop/django-salmonella/salmonella/admin.py/SalmonellaMixin.formfield_for_manytomany/swapped operands of `in`