Copyright 2001 Gareth Rees.  All rights reserved.
Copyright 2004-2018 Ned Batchelder.  All rights reserved.

Except where noted otherwise, this software is licensed under the Apache
License, Version 2.0 (the "License"); you may not use this work 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.