code: def gen_feats(self, e_set):
          
          bag_feats = self.gen_bag_feats(e_set)
          length_feats = self.gen_length_feats(e_set)
          prompt_feats = self.gen_prompt_feats(e_set)
          overall_feats = numpy.concatenate((length_feats, prompt_feats, bag_feats), axis=1)
          overall_feats = overall_feats.copy()
  
          return overall_feats
docs: Generates bag of words, length, and prompt features from an essay set object
          returns an array of features
          e_set - EssaySet object