To keep score in the game, the following line of code is used:
players[i]["score"] += 1
You will notice a new symbol, +=. The += symbol is a shortcut that lets us take a value (score), add an amount to this value (we are adding 1 point), and then make the value of score equal to the new value.
This line of code says that if the first player makes a match to an item in the second player backpack, then the new score for the first player is score += 1. You will remember that in the beginning of the game, we set each player to have a score of zero in the dictionary. Now, we are updating that score to be score += 1. Each time the first player scores, score will be updated by 1, and the computer will remember the new score.