'Returns the distance from the given geographic field name to the
given geometry in a `distance` attribute on each element of the
GeoQuerySet.
Keyword Arguments:
`spheroid`  => If the geometry field is geodetic and PostGIS is
the spatial database, then the more accurate
spheroid calculation will be used instead of the
quicker sphere calculation.
`tolerance` => Used only for Oracle. The tolerance is
in meters -- a default of 5 centimeters (0.05)
is used.'

def distance(self, geom, **kwargs):

    return self._distance_attribute('distance', geom, **kwargs)
