code: def str_def(self):
          
          return "classname={!r}; operation_timeout={!r}; message={!r};". \
              format(self.__class__.__name__, self.operation_timeout,
                     self.args[0])
docs: :term:`string`: The exception as a string in a Python definition-style
          format, e.g. for parsing by scripts:
  
          .. code-block:: text
  
              classname={}; operation_timeout={}; message={};