How frequently is 7 in randomly generated code?

from random import choice
from datetime import datetime
import sys

with open("77777.txt", "a") as f:  # open file with write access
    # Saving the reference of the standard output
    original_stdout = sys.stdout

    sys.stdout = f

    print(70 * "*")
    print("How frequently will randomly generated code contain digit 7 ?")
    print(70 * "*")

    number_of_digits = 5
    print(f"Number of digits: {number_of_digits}")
    values = [_ for _ in range(1, 9)]
    print(f"Possible values: {values}")
    counter_of_luck = [0 for _ in range(0, number_of_digits + 1)]

    generated_codes = 333333
    print(f"Number of generated codes: {generated_codes}")
    print(70 * "*")
    for secret_code_index in range(0, generated_codes):
        secret_code = ""
        for a in range(0, number_of_digits):
            secret_code += str(choice(values))
        seven = [digit for digit in secret_code if digit == "7"]
        counter_of_luck[len(seven)] += 1

    for lucky_pointer in range(0, len(counter_of_luck)):
        print(
            f"Number of 7 :{lucky_pointer}. Number of codes: {counter_of_luck[lucky_pointer]}.   "
            f"It is {counter_of_luck[lucky_pointer]*100/generated_codes} % cases."
        )

    # Reset the standard output
    sys.stdout = original_stdout

    print("This message will be written to the screen.")