Wrote a new goal in yahtzee_goals.py

I'm not sure if I underdtood it correctly. But, I found that it broke down a large piece of code into smaller pices like a code for dice, goals, and the game. Additionally, it also made it easier to test and change codes if needed.

play.py

@@ -3,12 +3,14 @@ from yahtzee_goals import (
     GoalOnes, 
     GoalTwos, 
     GoalThrees,
+    GoalFours
 )
 
 goals = [
     GoalOnes(), 
     GoalTwos(),
     GoalThrees(),
+    GoalFours(),
 ]
 
 game = Yahtzee(goals)

yahtzee_goals.py

@@ -40,3 +40,17 @@ class GoalThrees:
             if die.face == 3:
                 total += 3
         return total
+    
+class GoalFours:
+    "Four points for each four"
+
+    def prompt(self, dice):
+        potential_score = self.score(dice)
+        return f"Fours ({potential_score})"
+
+    def score(self, dice):
+        total = 0
+        for die in dice:
+            if die.face == 4:
+                total += 4
+        return total