The Hangman Game

The initial part of the code of the game "The Hangman Game", with the import of the modules/packages and the initialization of the constants and global variables.

The game saves each letter used, to allow the user to know which of these have already been chosen;
in case the user chooses a letter that has already been used, the game ignores the user's choice and waits for further input.

In case the player guesses the hidden word, the number of attempts left to guess the word is shown on the screen, and the player is asked if he wants to play another game.

In case the player doesn't guess the hidden word, it is shown on the screen and the player is asked if he wants to play another game.