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 oslo_config import cfg
  
  from keystone.conf import utils
  
  
  driver = cfg.StrOpt(
      'driver',
      default='sql',
      help=utils.fmt("""
  Entry point for the unified limit backend driver in the
  `keystone.unified_limit` namespace. Keystone only provides a `sql` driver, so
  there's no reason to change this unless you are providing a custom entry point.
  """))
  
  caching = cfg.BoolOpt(
      'caching',
      default=True,
      help=utils.fmt("""
  Toggle for unified limit caching. This has no effect unless global caching is
  enabled. In a typical deployment, there is no reason to disable this.
  """))
  
  cache_time = cfg.IntOpt(
      'cache_time',
      help=utils.fmt("""
  Time to cache unified limit data, in seconds. This has no effect unless both
  global caching and `[unified_limit] caching` are enabled.
  """))
  
  list_limit = cfg.IntOpt(
      'list_limit',
      help=utils.fmt("""
  Maximum number of entities that will be returned in a role collection. This may
  be useful to tune if you have a large number of unified limits in your
  deployment.
  """))
  
  
  GROUP_NAME = __name__.split('.')[-1]
  ALL_OPTS = [
      driver,
      caching,
      cache_time,
      list_limit,
  ]
  
  
  def register_opts(conf):
      conf.register_opts(ALL_OPTS, group=GROUP_NAME)
  
  
  def list_opts():
      return {GROUP_NAME: ALL_OPTS}
  
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 oslo_config import cfg
  
  from keystone.conf import utils
  
  
  driver = cfg.StrOpt(
      'driver',
      default='sql',
      help=utils.fmt("""
  Entry point for the unified limit backend driver in the
  `keystone.unified_limit` namespace. Keystone only provides a `sql` driver, so
  there's no reason to change this unless you are providing a custom entry point.
  """))
  
  caching = cfg.BoolOpt(
      'caching',
      default=True,
      help=utils.fmt("""
  Toggle for unified limit caching. This has no effect unless global caching is
  enabled. In a typical deployment, there is no reason to disable this.
  """))
  
  cache_time = cfg.IntOpt(
      'cache_time',
      help=utils.fmt("""
  Time to cache unified limit data, in seconds. This has no effect unless both
  global caching and `[unified_limit] caching` are enabled.
  """))
  
  list_limit = cfg.IntOpt(
      'list_limit',
      help=utils.fmt("""
  Maximum number of entities that will be returned in a role collection. This may
  be useful to tune if you have a large number of unified limits in your
  deployment.
  """))
  
  enforcement_model = cfg.StrOpt(
      'enforcement_model',
      default='flat',
      choices=['flat'],
      help=utils.fmt("""
  The enforcement model to use when validating limits associated to projects.
  Enforcement models will behave differently depending on the existing limits,
  which may result in backwards incompatible changes if a model is switched in a
  running deployment.
  """))
  
  
  GROUP_NAME = __name__.split('.')[-1]
  ALL_OPTS = [
      driver,
      caching,
      cache_time,
      list_limit,
      enforcement_model,
  ]
  
  
  def register_opts(conf):
      conf.register_opts(ALL_OPTS, group=GROUP_NAME)
  
  
  def list_opts():
      return {GROUP_NAME: ALL_OPTS}
  
subject: Add configuration option for enforcement models