title: plot roc curve of diffenret models on same graphics
body: <p>how to plot roc curves of different models on same graphics please?
  I did this but how to continue please!,</p>
  
  <pre><code>from matplotlib import pyplot
  probaA= model.predict_proba(X_testA)[:, 1]
  probaB = model.predict_proba(X_testB)[:, 1] 
  fpr, tpr, _ = metrics.roc_curve(y_testA,  probaA)
  auc = metrics.roc_auc_score(y_testA, probaA)
  pyplot.plot([0, 1], [0, 1], linestyle='--')
  plt.plot(fpr,tpr,label="auc="+str(auc))
  plt.legend(loc=4)
  plt.show()
  </code></pre>