new_contents: # -*- coding: utf-8 -*-
  # BSD 3-Clause License
  #
  # Copyright (c) 2008-2012, AQR Capital Management, LLC, Lambda Foundry, Inc.
  # and PyData Development Team
  # All rights reserved.
  #
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  # modification, are permitted provided that the following conditions are met:
  #
  # * Redistributions of source code must retain the above copyright notice, this
  #   list of conditions and the following disclaimer.
  #
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  #   this list of conditions and the following disclaimer in the documentation
  #   and/or other materials provided with the distribution.
  #
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  #   contributors may be used to endorse or promote products derived from
  #   this software without specific prior written permission.
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  # AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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  # ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
  # LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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  # ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
  # THE POSSIBILITY OF SUCH DAMAGE.
  """Appender class from pandas.util._decorators ."""
  from textwrap import dedent
  from typing import Any, Callable, Optional, TypeVar
  
  FuncType = Callable[..., Any]
  F = TypeVar('F', bound=FuncType)
  
  
  class Appender:  # pylint: disable=too-few-public-methods
      """
      A function decorator that will append an addendum to the docstring
      of the target function.
      This decorator should be robust even if func.__doc__ is None
      (for example, if -OO was passed to the interpreter).
      Usage: construct a docstring.Appender with a string to be joined to
      the original docstring. An optional 'join' parameter may be supplied
      which will be used to join the docstring and addendum. e.g.
      add_copyright = Appender("Copyright (c) 2009", join='\n')
      @add_copyright
      def my_dog(has='fleas'):
          "This docstring will have a copyright below"
          pass
      """
  
      def __init__(self,
                   addendum: Optional[str],
                   join: str = '',
                   indents: int = 0):
          if indents > 0:
              # type: Optional[str]
              self.addendum = indent(addendum, indents=indents)
          else:
              self.addendum = addendum
          self.join = join
  
      def __call__(self, func: F) -> F:
          func.__doc__ = func.__doc__ if func.__doc__ else ''
          self.addendum = self.addendum if self.addendum else ''
          docitems = [func.__doc__, self.addendum]
          func.__doc__ = dedent(self.join.join(docitems))
          return func
  
  
  def indent(text: Optional[str], indents: int = 1) -> str:
      """Indent docstring text"""
      if not text or not isinstance(text, str):
          return ''
      jointext = ''.join(['\n'] + ['    '] * indents)
      return jointext.join(text.split('\n'))
  
subject: add appender module