Update a comment's function name reference.

hw_sentiment.ipynb

@@ -578,7 +578,7 @@
     "\n",
     "1. Take as inputs (a) a model training wrapper like `fit_softmax_classifier` and (b) an integer `bakeoff_train_size` specifying the number of examples from `bakeoff_dev` that should be included in the train set.\n",
     "1. Split `bakeoff_dev` so that the first `bakeoff_train_size` examples are in the train set and the rest are used for evaluation.\n",
-    "1. Use `sst.experiment` with the user-supplied model training wrapper, `unigram_phi` as defined above, and a train set that consists of SST-3 train and the train portion of `bakeoff_dev` as defined in step 2. The value of `assess_dataframes` should be a list consisting of the SST-3 dev set and the evaluation portion of `bakeoff_dev` as defined in step 2.\n",
+    "1. Use `sst.experiment` with the user-supplied model training wrapper, `unigrams_phi` as defined above, and a train set that consists of SST-3 train and the train portion of `bakeoff_dev` as defined in step 2. The value of `assess_dataframes` should be a list consisting of the SST-3 dev set and the evaluation portion of `bakeoff_dev` as defined in step 2.\n",
     "1. Return the return value of `sst.experiment`.\n",
     "\n",
     "The function `test_run_mixed_training_experiment` will help you iterate to the required design."