old_contents: #
  # Licensed under the Apache License, Version 2.0 (the "License"); you may
  # not use this file except in compliance with the License. You may obtain
  # a copy of the License at
  #
  #      http://www.apache.org/licenses/LICENSE-2.0
  #
  # Unless required by applicable law or agreed to in writing, software
  # distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
  # WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
  # License for the specific language governing permissions and limitations
  # under the License.
  #
  
  from neutron_lib.api import extensions
  from neutron_lib import constants
  
  
  EXTENDED_ATTRIBUTES_2_0 = {
      'routers': {
          'flavor_id': {'allow_post': True, 'allow_put': False,
                        'default': constants.ATTR_NOT_SPECIFIED,
                        'is_visible': True, 'enforce_policy': True}
  
      }
  }
  
  
  class L3_flavors(extensions.ExtensionDescriptor):
      """Extension class supporting flavors for routers."""
  
      @classmethod
      def get_name(cls):
          return "Router Flavor Extension"
  
      @classmethod
      def get_alias(cls):
          return 'l3-flavors'
  
      @classmethod
      def get_description(cls):
          return "Flavor support for routers."
  
      @classmethod
      def get_updated(cls):
          return "2016-05-17T00:00:00-00:00"
  
      def get_extended_resources(self, version):
          if version == "2.0":
              return EXTENDED_ATTRIBUTES_2_0
          else:
              return {}
  
      def get_required_extensions(self):
          return ["router", "flavors"]
  
new_contents: #
  # Licensed under the Apache License, Version 2.0 (the "License"); you may
  # not use this file except in compliance with the License. You may obtain
  # a copy of the License at
  #
  #      http://www.apache.org/licenses/LICENSE-2.0
  #
  # Unless required by applicable law or agreed to in writing, software
  # distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
  # WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
  # License for the specific language governing permissions and limitations
  # under the License.
  #
  
  from neutron_lib.api.definitions import l3_flavors as apidef
  from neutron_lib.api import extensions
  
  
  class L3_flavors(extensions.APIExtensionDescriptor):
      """Extension class supporting flavors for routers."""
  
      api_definition = apidef
  
subject: use l3 flavors api def from neutron-lib