old_contents: # Rx Exceptions
  
  
  from typing import Optional
  
  
  class SequenceContainsNoElementsError(Exception):
      def __init__(self, msg: Optional[str] = None):
          super(SequenceContainsNoElementsError, self).__init__(
              msg or "Sequence contains no elements"
          )
  
  
  class ArgumentOutOfRangeException(ValueError):
      def __init__(self, msg: Optional[str] = None):
          super(ArgumentOutOfRangeException, self).__init__(
              msg or "Argument out of range"
          )
  
  
  class DisposedException(Exception):
      def __init__(self, msg: Optional[str] = None):
          super().__init__(msg or "Object has been disposed")
  
  
  class ReEntracyException(Exception):
      def __init__(self, msg: Optional[str] = None):
          super().__init__(msg or "Re-entrancy detected")
  
  
  class CompletedException(Exception):
      def __init__(self, msg: Optional[str] = None):
          super().__init__(msg or "Observer completed")
  
  
  class WouldBlockException(Exception):
      def __init__(self, msg: Optional[str] = None):
          super().__init__(msg or "Would block")
  
new_contents: # Rx Exceptions
  
  
  from typing import Optional
  
  
  class SequenceContainsNoElementsError(Exception):
      def __init__(self, msg: Optional[str] = None):
          super().__init__(msg or "Sequence contains no elements")
  
  
  class ArgumentOutOfRangeException(ValueError):
      def __init__(self, msg: Optional[str] = None):
          super(ArgumentOutOfRangeException, self).__init__(
              msg or "Argument out of range"
          )
  
  
  class DisposedException(Exception):
      def __init__(self, msg: Optional[str] = None):
          super().__init__(msg or "Object has been disposed")
  
  
  class ReEntracyException(Exception):
      def __init__(self, msg: Optional[str] = None):
          super().__init__(msg or "Re-entrancy detected")
  
  
  class CompletedException(Exception):
      def __init__(self, msg: Optional[str] = None):
          super().__init__(msg or "Observer completed")
  
  
  class WouldBlockException(Exception):
      def __init__(self, msg: Optional[str] = None):
          super().__init__(msg or "Would block")
  
subject: Use python 3 super