old_contents: # --------------------------------------------------------------------------
  #
  # Copyright (c) Microsoft Corporation. All rights reserved.
  #
  # The MIT License (MIT)
  #
  # Permission is hereby granted, free of charge, to any person obtaining a copy
  # of this software and associated documentation files (the ""Software""), to
  # deal in the Software without restriction, including without limitation the
  # rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
  # sell copies of the Software, and to permit persons to whom the Software is
  # furnished to do so, subject to the following conditions:
  #
  # The above copyright notice and this permission notice shall be included in
  # all copies or substantial portions of the Software.
  #
  # THE SOFTWARE IS PROVIDED *AS IS*, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  # FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  # AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  # FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  # IN THE SOFTWARE.
  #
  # --------------------------------------------------------------------------
  
  from .base import HTTPPolicy, SansIOHTTPPolicy
  from .credentials import BearerTokenCredentialPolicy
  from .redirect import RedirectPolicy
  from .retry import RetryPolicy
  from .universal import (
      HeadersPolicy,
      UserAgentPolicy,
      NetworkTraceLoggingPolicy,
      ContentDecodePolicy,
      ProxyPolicy
  )
  
  __all__ = [
      'HTTPPolicy',
      'SansIOHTTPPolicy',
      'BearerTokenCredentialPolicy',
      'HeadersPolicy',
      'UserAgentPolicy',
      'NetworkTraceLoggingPolicy',
      'ContentDecodePolicy',
      'RetryPolicy',
      'RedirectPolicy',
      'ProxyPolicy',
      'CustomHookPolicy'
  ]
  
  try:
      from .base_async import AsyncHTTPPolicy
      from .credentials_async import AsyncBearerTokenCredentialPolicy
      from .redirect_async import AsyncRedirectPolicy
      from .retry_async import AsyncRetryPolicy
      __all__.extend([
          'AsyncHTTPPolicy',
          'AsyncBearerTokenCredentialPolicy',
          'AsyncRedirectPolicy',
          'AsyncRetryPolicy'
      ])
  except (ImportError, SyntaxError):
      pass  # Async not supported
  
new_contents: # --------------------------------------------------------------------------
  #
  # Copyright (c) Microsoft Corporation. All rights reserved.
  #
  # The MIT License (MIT)
  #
  # Permission is hereby granted, free of charge, to any person obtaining a copy
  # of this software and associated documentation files (the ""Software""), to
  # deal in the Software without restriction, including without limitation the
  # rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
  # sell copies of the Software, and to permit persons to whom the Software is
  # furnished to do so, subject to the following conditions:
  #
  # The above copyright notice and this permission notice shall be included in
  # all copies or substantial portions of the Software.
  #
  # THE SOFTWARE IS PROVIDED *AS IS*, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  # FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  # AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  # FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  # IN THE SOFTWARE.
  #
  # --------------------------------------------------------------------------
  
  from .base import HTTPPolicy, SansIOHTTPPolicy
  from .credentials import BearerTokenCredentialPolicy
  from .custom_hook import CustomHookPolicy
  from .redirect import RedirectPolicy
  from .retry import RetryPolicy
  from .universal import (
      HeadersPolicy,
      UserAgentPolicy,
      NetworkTraceLoggingPolicy,
      ContentDecodePolicy,
      ProxyPolicy
  )
  
  __all__ = [
      'HTTPPolicy',
      'SansIOHTTPPolicy',
      'BearerTokenCredentialPolicy',
      'HeadersPolicy',
      'UserAgentPolicy',
      'NetworkTraceLoggingPolicy',
      'ContentDecodePolicy',
      'RetryPolicy',
      'RedirectPolicy',
      'ProxyPolicy',
      'CustomHookPolicy'
  ]
  
  try:
      from .base_async import AsyncHTTPPolicy
      from .credentials_async import AsyncBearerTokenCredentialPolicy
      from .redirect_async import AsyncRedirectPolicy
      from .retry_async import AsyncRetryPolicy
      __all__.extend([
          'AsyncHTTPPolicy',
          'AsyncBearerTokenCredentialPolicy',
          'AsyncRedirectPolicy',
          'AsyncRetryPolicy'
      ])
  except (ImportError, SyntaxError):
      pass  # Async not supported
  
subject: add missing import (#5340)