'Modify Snapshot attributes.
:param      snapshot: VolumeSnapshot instance
:type       snanpshot: :class:`VolumeSnapshot`
:param      attributes: Dictionary with snapshot attributes
:type       attributes: ``dict``
:return: True on success, False otherwise.
:rtype: ``bool``'

def ex_modify_snapshot_attribute(self, snapshot, attributes):

    attributes = (attributes or {})
    attributes.update({'SnapshotId': snapshot.id})
    params = {'Action': 'ModifySnapshotAttribute'}
    params.update(attributes)
    res = self.connection.request(self.path, params=params.copy()).object
    return self._get_boolean(res)
