import ROOT

#reading file and getting histogram
file  = ROOT.TFile("output.root","READ")
hist  = file.Get("h1")

hist.SetStats(0) #turn off statistics box
hist.SetTitle("")
hist.SetLineColor(ROOT.kRed)
hist.SetLineWidth(2)
hist.GetYaxis().SetTitle("Events")
hist.GetXaxis().SetTitle("m_{Z} (in GeV)")

c1 = ROOT.TCanvas("canvas")
c1.cd()
hist.Draw()
c1.Print("hist.png")