old_contents: """Beaker exception classes"""
  
  class BeakerException(Exception):
      pass
  
  
  class CreationAbortedError(Exception):
      """deprecated."""
  
  class InvalidCacheBackendError(BeakerException):
      pass
  
  
  class MissingCacheParameter(BeakerException):
      pass
  
  
  class LockError(BeakerException):
      pass
  
new_contents: """Beaker exception classes"""
  
  class BeakerException(Exception):
      pass
  
  
  class CreationAbortedError(Exception):
      """deprecated."""
  
  class InvalidCacheBackendError(BeakerException, ImportError):
      pass
  
  
  class MissingCacheParameter(BeakerException):
      pass
  
  
  class LockError(BeakerException):
      pass
  
subject: make InvalidCacheBackendError a subclass of ImportError, it's rather annoying otherwise