diff --git a/neutron/tests/tempest/api/test_network_ip_availability.py b/neutron/tests/tempest/api/test_network_ip_availability.py
index 74395ea..6a81128 100644
--- a/neutron/tests/tempest/api/test_network_ip_availability.py
+++ b/neutron/tests/tempest/api/test_network_ip_availability.py
@@ -86,7 +86,7 @@
             mask_bits = config.safe_get_config_value(
                 'network', 'project_network_v6_mask_bits')
 
-        subnet_cidr = cidr.subnet(mask_bits).next()
+        subnet_cidr = next(cidr.subnet(mask_bits))
         prefix_len = subnet_cidr.prefixlen
         subnet = self.create_subnet(network,
                                     cidr=subnet_cidr,