import numpy as np
import ROOT

c2 = ROOT.TCanvas("c2", "", 700, 500)

c2.SetGrid()
npoints = 3
xaxis = np.array([1.0, 2.0, 3.0])
yaxis = np.array([10.0, 20.0, 30.0])

exl = np.array([0.5, 0.2, 0.1])  # Lower x errors
exh = np.array([0.5, 0.3, 0.4])  # Higher x errors
eyl = np.array([3.0, 5.0, 4.0])  # Lower y errors
eyh = np.array([3.0, 5.0, 4.0])  # Higher y errors

gr = ROOT.TGraphAsymmErrors(
    npoints, xaxis, yaxis, exl, exh, eyl, eyh
)  # Create the TGraphAsymmErrors object with data and asymmetrical errors

gr.SetTitle("A simple graph with asymmetrical errors")
gr.Draw("A*")  # "A" = draw axes and "*" = draw markers at the points with error bars