How to put matplot lib graph into tkinter window

matplotlib_in_tkinter.py

# minimal example on how to put matplot lib graph into tkinter window
import tkinter as tk
import matplotlib.backends.backend_tkagg as tka
from matplotlib.figure import Figure
import numpy as np

win = tk.Tk()
fig = Figure()
canvas = tka.FigureCanvasTkAgg(fig, win)
toolbar = tka.NavigationToolbar2Tk(canvas, win)
canvas.get_tk_widget().pack()

ax = fig.add_subplot()
ax.scatter(1, 1)
ax.scatter(2, 4)

def on_click():
    ax.scatter(3, 9)
    canvas.draw()

button = tk.Button(win, text="add", command=on_click)
button.pack(side=tk.BOTTOM)

win.mainloop()