Bulls and Cows game

Simple and old numerical game where a player is trying to guess unknown 4-digit number.

Solution to this task https://github.com/engetoacademy/pythontask

Sample game

Hi there!
Let's play a bulls and cows game.
I've generated a random 4-digit number for you.
Guess that number
1234
0 bulls, 1 cow
7638
0 bulls, 2 cows
6387
2 bulls, 0 cows
6353
Numbers must not be repeated.
6354
2 bulls, 1 cow
635
Too short. Please enter 4-digit integer.
6350
2 bulls, 2 cows
6305
Correct, you've guessed the right number in 6 guesses!
That's really good.
Do you want to play again? (Y/N) n
Thank you for playing! Bye bye.