How to get point values from TMultiGraph?


I want to get point values from TMultiGraph.
If I have TGraph object I can write this code:

const int N_points = graph->GetN();
double x, y;
for(int i=0; i < N_points; i++)
	graph->GetPoint(i, x, y); 
	cout << "f(" << x << ") =" << y <<endl;

But how to do this in case of TMultiGraph object, if I have several graphs in it?
I don’t see sothing like GetPoint().
Could you help me?

Thank you in advance.
Best regards, Vladislav.

I found this talk:

But how to iterate?
Could you give simple working example?

This one gives an example: