old_contents: class AuthError(Exception):
      def __init__(self, value):
          self.value = value
  
      def __str__(self):
          return self.value
  
  
  class SendError(Exception):
      def __init__(self, value):
          self.value = value
  
      def __str__(self):
          return self.value
  
  
  class MiscError(Exception):
      def __init__(self, value):
          self.value = value
  
      def __str__(self):
          return self.value
  
  
new_contents: class AuthError(Exception):
      def __init__(self, value):
          self.value = value
  
  
  class SendError(Exception):
      def __init__(self, value):
          self.value = value
  
  
  class MiscError(Exception):
      def __init__(self, value):
          self.value = value
  
subject: Remove unused __str__ methods