code: def get_quota(self):
  		'Return tuple of (bytes_available, bytes_quota).'
  		du, ds = op.itemgetter('used_bytes', 'max_bytes')((yield self()))
  		defer.returnValue((ds - du, ds)f get_quota(self):
  		'Return tuple of (bytes_available, bytes_quota).'
  		du, ds = op.itemgetter('used_bytes', 'max_bytes')((yield self()))
  		defer.returnValue((ds - du, ds))
docs: Return tuple of (bytes_available, bytes_quota).