On average how many times do you need to roll a die before all six different numbers show up?

die.py

# On average how many times do you need to roll a die before all six different numbers show up?

import random

dado = [i for i in range (1,7)]

throw_list = []
N = 100000       # montecarlo method
for i in range(N):
    lista = []
    throw = 0
    while len(lista) != 6 :  # the while condition stops only when all the six value are in the lista
        x = random.choice(dado)
        if x not in lista:   # we add the value in the list only if it doesn't exist yet
           lista.append(x)
        throw += 1
    throw_list.append(throw)

print("On average i need to roll the die {} before all six numbers show up.".format(float(sum(throw_list) / N)))