code: def observe(self, algorithm):
          
          if self.__observing:
              raise RuntimeError('This error observer is already observing an algorithm.')
          if hasattr(algorithm, 'GetExecutive') and algorithm.GetExecutive() is not None:
              algorithm.GetExecutive().AddObserver(self.event_type, self)
          algorithm.AddObserver(self.event_type, self)
          self.__observing = True
          return
docs: Make this an observer of an algorithm