import random
import matplotlib.pyplot as plt
def Ehrenfest(N,n):
    A =[i for i in range (1,N + 1)]
    Xn …
    for k in range (n):
        b = random.randint(1,N)
        if b in A:
        …
        else :
        …
        Xn.append(…)
    return Xn