'Verifies the geometry -- will construct and return a GeometryCollection
if necessary (for example if the model field is MultiPolygonField while
the mapped shapefile only contains Polygons).'

def verify_geom(self, geom, model_field):

    if (self.coord_dim != geom.coord_dim):
        geom.coord_dim = self.coord_dim
    if self.make_multi(geom.geom_type, model_field):
        multi_type = self.MULTI_TYPES[geom.geom_type.num]
        g = OGRGeometry(multi_type)
        g.add(geom)
    else:
        g = geom
    if self.transform:
        g.transform(self.transform)
    return g.wkt
