- ax.plot(x_test, y_test, color = 'blue', label = 'Test values')
- ax.scatter(x_train, y_train, color = 'blue', label = 'Training examples')
+ ax.plot(x_test, y_test, color = 'black', label = 'Test values')
+ ax.scatter(x_train, y_train, color = 'blue', label = 'Train samples')