old_contents: import warnings
  import functools
  
  
  class ObsoleteException(BaseException):
      """ Base class for warnings about obsolete features. """
      pass
  
  
  def obsolete_client(func):
      '''This is a decorator which can be used to mark Client classes
      as obsolete. It will result in an error being emitted
      when the class is instantiated.'''
  
      @functools.wraps(func)
      def new_func(*args, **kwargs):
          raise ObsoleteException("{} has been removed from this version of the library. "
                                "Please refer to current documentation for guidance."
                                .format(func.__name__))
  
      return new_func
  
new_contents: import warnings
  import functools
  
  
  class ObsoleteException(BaseException):
      """ Base class for warnings about obsolete features. """
      pass
  
  
  def obsolete_client(func):
      """This is a decorator which can be used to mark Client classes as
      obsolete. It will result in an error being emitted when the class is
      instantiated."""
  
      @functools.wraps(func)
      def new_func(*args, **kwargs):
          raise ObsoleteException(
              "{} has been removed from this version of the library. "
              "Please refer to current documentation for guidance."
              .format(func.__name__)
          )
  
      return new_func
  
subject: Fix spacing