message: update deprecated pandas call
  pd.scatter_matrix -> pd.plotting.scatter_matrix
diff: "# Visualize sample of the data\n",
  "ind = np.random.permutation(X.shape[0])[:1000]\n",
  "df = pd.DataFrame(X[ind])\n",
  - "_ = pd.scatter_matrix(df, figsize=(9, 9), diagonal='kde', marker='o', s=40, alpha=.4, c=y[ind])"
  + "_ = pd.plotting.scatter_matrix(df, figsize=(9, 9), diagonal='kde', marker='o', s=40, alpha=.4, c=y[ind])"
  ]
  },
  {
  