'Update an encryption type for an existing volume type.
For a full list of available parameters, please refer to the official
API reference:
https://developer.openstack.org/api-ref/block-storage/v2/#update-an-encryption-type-for-v2'

def update_encryption_type(self, volume_type_id, **kwargs):

    url = ('/types/%s/encryption/provider' % volume_type_id)
    put_body = json.dumps({'encryption': kwargs})
    (resp, body) = self.put(url, put_body)
    body = json.loads(body)
    self.expected_success(200, resp.status)
    return rest_client.ResponseBody(resp, body)
