# coding=utf-8
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# or more contributor license agreements.  See the NOTICE file
# distributed with this work for additional information
# regarding copyright ownership.  The ASF licenses this file
# to you 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
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import threading


def get_user_agent():
    return UserAgentManager.user_agent


def register_user_agent(user_agent, priority):
    if priority >= UserAgentManager.priority:
        with UserAgentManager.lock:
            if priority >= UserAgentManager.priority:
                UserAgentManager.user_agent = user_agent
                UserAgentManager.priority = priority


class UserAgentManager:
    user_agent = None
    priority = 0
    lock = threading.RLock()
