code: def get_or_exception(cls, id):
          ''' Tries to retrieve an instance of this model from the database or
          raises an exception in case of failure '''
          obj = cls.get(id)
  
          if obj is None:
              raise ModelNotFoundError('This object does not exist in database')
  
          return obf get_or_exception(cls, id):
          ''' Tries to retrieve an instance of this model from the database or
          raises an exception in case of failure '''
          obj = cls.get(id)
  
          if obj is None:
              raise ModelNotFoundError('This object does not exist in database')
  
          return obj
docs: Tries to retrieve an instance of this model from the database or
          raises an exception in case of failure