'Returns a GeoHash representation of the given field in a `geohash`
attribute on each element of the GeoQuerySet.
The `precision` keyword may be used to custom the number of
_characters_ used in the output GeoHash, the default is 20.'

def geohash(self, precision=20, **kwargs):

    s = {'desc': 'GeoHash', 'procedure_args': {'precision': precision}, 'procedure_fmt': '%(geo_col)s,%(precision)s'}
    return self._spatial_attribute('geohash', s, **kwargs)
