I have a graph with its errors. I create a fit function for that graph. And I want to draw fit function with its errors. Could you help me, please?

```
#include <TGraphErrors.h>
#include <TCanvas.h>
#include <TF1.h>
#include <TVirtualFitter.h>
void alo()
{
TCanvas *c = new TCanvas("c","alo",700,500);
c->SetGrid();
TGraphErrors *g = new TGraphErrors("cm0.txt");
g->Draw("AP");
g->SetMarkerStyle(8);
TF1 *fit =new TF1("fit", "exp([0] + [1]*log(x) + [2]*((log(x))^2) + [3]*((log(x))^3))", 0 , 2000);
g->Fit("fit");
TVirtualFitter::GetFitter()->GetConfidenceIntervals(g, 0.95);
}
```

Here is my code and plot. But the uncertainty of fit function wasnâ€™t draw.