I keep getting an error message saying 'During the algorithm initialization, the following exception has occurred: NameError : name 'NewsSentimentAlphaModel' is not defined at Initialize in main.py:line 19 :: self.SetAlpha(NewsSentimentAlphaModel()) NameError : name 'NewsSentimentAlphaModel' is not defined'

However, my code seems to be correct and is an exact replica of the solution code. Why do I get this response ?Please see the image below -Thanks,