A clinic wants a shorter test. You score each of the thirty columns on its own against the diagnosis and keep the strongest few.
Task: write kbest_columns(k).
load_breast_cancer(return_X_y=True, as_frame=True).train_test_split(X, y, test_size=0.25, random_state=0, stratify=y).SelectKBest(f_classif, k=k) on the training rows.Return the names of the kept columns as a list, in the order they appear in the data.