I am getting this error in Ridge.fit() is it because of targets shape?
This is link to my notebook 
notebook_link
You have an instance of Ridge class named model.
You try to use fit() method on the class instead of the instance.
So your train_inputs become self, train_targets become X, and the y is really missing here.
Replace Ridge.fit with model.fit
ohh damn.sorry for such silly doubt 