def test_feature_names_out(): """Check `get_feature_names_out` for `Birch`.""" X, _ = make_blobs(n_samples=80, n_features=4, random_state=0) brc = Birch(n_clusters=4) brc.fit(X) n_clusters = brc.subcluster_centers_.shape[0] names_out = brc.get_feature_names_out() assert_array_equal([f"birch{i}" for i in range(n_clusters)], names_out)