import ROOT

ROOT.gStyle.SetOptStat(0)

c1 = ROOT.TCanvas("c1", "fit residual simple")
h1 = ROOT.TH1D("h1", "h1", 50, -5, 5)
h1.FillRandom("gaus", 2000)
h1.Fit("gaus")
h1.GetXaxis().SetTitle("x")
h1.GetYaxis().SetTitle("y")

rp1 = ROOT.TRatioPlot(h1)

lines = ROOT.std.vector('double')()
for i in range(-3,4):lines.push_back(i)
rp1.SetGridlines(lines)

rp1.Draw()
rp1.GetLowerRefGraph().SetMinimum(-4)
rp1.GetLowerRefGraph().SetMaximum(4)

c1.Update()