def get_db_prep_lookup(self, lookup_type, value, connection=None, prepared=False):
        if lookup_type not in ['exact', 'in', 'isnull']:
            raise TypeError('Lookup type %s is not supported.' % lookup_type)
        # The Field model already calls get_db_prep_value before doing the
        # actual lookup, so all we need to do is limit the lookup types.
        try:
            return super(PickledObjectField, self).get_db_prep_lookup(
                lookup_type, value, connection=connection, prepared=prepared)
        except __HOLE__:
            # Try not to break on older versions of Django, where the
            # `connection` and `prepared` parameters are not available.
            return super(PickledObjectField, self).get_db_prep_lookup(
                lookup_type, value)


# South support; see http://south.aeracode.org/docs/tutorial/part4.html#simple-inheritance
dataset/ETHPy150Open callowayproject/django-supertagging/supertagging/fields.py/PickledObjectField.get_db_prep_lookup