old_contents: #!/usr/bin/env python3
  """Exception classes shared by all automata."""
  
  
  class AutomatonException(Exception):
      """The base class for all automaton-related errors."""
  
      pass
  
  
  class InvalidStateError(AutomatonException):
      """A state is not a valid state for this automaton."""
  
      pass
  
  
  class InvalidSymbolError(AutomatonException):
      """A symbol is not a valid symbol for this automaton."""
  
      pass
  
  
  class MissingStateError(AutomatonException):
      """A state is missing from the automaton definition."""
  
      pass
  
  
  class MissingSymbolError(AutomatonException):
      """A symbol is missing from the automaton definition."""
  
      pass
  
  
  class InitialStateError(AutomatonException):
      """The initial state fails to meet some required condition."""
  
      pass
  
  
  class FinalStateError(AutomatonException):
      """A final state fails to meet some required condition."""
  
      pass
  
  
  class RejectionException(AutomatonException):
      """The input was rejected by the automaton after validation."""
  
      pass
  
new_contents: #!/usr/bin/env python3
  """Exception classes shared by all automata."""
  
  
  class AutomatonException(Exception):
      """The base class for all automaton-related errors."""
  
      pass
  
  
  class InvalidStateError(AutomatonException):
      """A state is not a valid state for this automaton."""
  
      pass
  
  
  class InvalidSymbolError(AutomatonException):
      """A symbol is not a valid symbol for this automaton."""
  
      pass
  
  
  class MissingStateError(AutomatonException):
      """A state is missing from the automaton definition."""
  
      pass
  
  
  class MissingSymbolError(AutomatonException):
      """A symbol is missing from the automaton definition."""
  
      pass
  
  
  class InitialStateError(AutomatonException):
      """The initial state fails to meet some required condition."""
  
      pass
  
  
  class FinalStateError(AutomatonException):
      """A final state fails to meet some required condition."""
  
      pass
  
  
  class RejectionException(AutomatonException):
      """The input was rejected by the automaton."""
  
      pass
  
subject: Remove "validation" from RejectionException docstring