Hello, `GeoFeatureModelSerializer` fails to get bounding box when `geo_field` points to a `SerializerMethodField` ``` AttributeError: object has no attribute 'extent' ``` Example: ```python class PlaceSerializer(GeoFeatureModelSerializer): location = GeometrySerializerMethodField() class Meta: model = Location fields = ["name"] id_field = "pk" geo_field = "location" auto_bbox = True def get_location(self, obj): return obj.location.transform(4326, clone=True) ```