'Transforms the given geometry field to the given SRID.  If no SRID is
provided, the transformation will default to using 4326 (WGS84).'

def transform(self, srid=4326, **kwargs):

    if (not isinstance(srid, six.integer_types)):
        raise TypeError('An    integer    SRID    must    be    provided.')
    field_name = kwargs.get('field_name', None)
    (tmp, geo_field) = self._spatial_setup('transform', field_name=field_name)
    field_col = self._geocol_select(geo_field, field_name)
    geo_col = self.query.custom_select.get(geo_field, field_col)
    custom_sel = ('%s(%s,    %s)' % (connections[self.db].ops.transform, geo_col, srid))
    self.query.transformed_srid = srid
    self.query.custom_select[geo_field] = custom_sel
    return self._clone()
