diff --git a/.coverage b/.coverage
index 1fb750d5..cb7cf9a9 100644
Binary files a/.coverage and b/.coverage differ
diff --git a/python/gilded_rose.py b/python/gilded_rose.py
index d392139a..dfda4309 100755
--- a/python/gilded_rose.py
+++ b/python/gilded_rose.py
@@ -1,11 +1,22 @@
-# utf-8
+from typing import Final
+
+
+class Item:
+    def __init__(self, name, sell_in, quality):
+        self.name = name
+        self.sell_in = sell_in
+        self.quality = quality
+
+    def __repr__(self):
+        return "%s, %s, %s" % (self.name, self.sell_in, self.quality)
+
 
 class Updater(object):
     
-    MIN_QUALITY = 0
-    MAX_QUALITY = 50
+    MIN_QUALITY:Final[int] = 0
+    MAX_QUALITY: Final[int] = 50
 
-    def normal_item(self, item):
+    def normal_item(self, item:Item):
         if item.sell_in > 0: 
             depreciation = -1
         else:
@@ -13,7 +24,7 @@ class Updater(object):
         item.quality = max((item.quality + depreciation), self.MIN_QUALITY)
         item.sell_in += -1
 
-    def aged_brie(self, item):
+    def aged_brie(self, item:Item):
         if item.sell_in > 0:
             appreciation = 1
         else:
@@ -21,10 +32,10 @@ class Updater(object):
         item.quality = min((item.quality + appreciation), self.MAX_QUALITY)
         item.sell_in += -1
     
-    def sulfuras(self, item):
+    def sulfuras(self, item:Item):
         pass
 
-    def backstage_passes(self, item):
+    def backstage_passes(self, item:Item):
 
         def get_quality(item, appreciation):
             item.quality = min(item.quality + appreciation , self.MAX_QUALITY)
@@ -42,7 +53,7 @@ class Updater(object):
             item.quality = 0
         item.sell_in += -1
 
-    def conjured(self, item):
+    def conjured(self, item:Item):
         if item.sell_in > 0:
             depreciation = -2
         else:
@@ -54,31 +65,25 @@ class Updater(object):
 
 class GildedRose(object):
 
-    def __init__(self, items):
+    AGED_BRIE: Final[str] = "Aged Brie"
+    BACKSTAGE_PASSES: Final[str] = "Backstage passes to a TAFKAL80ETC concert"
+    SULFURAS: Final[str] = "Sulfuras, Hand of Ragnaros"
+    CONJURED: Final[str] = "Conjured Mana Cake"
+
+    def __init__(self, items:Item):
         self.items = items
 
     def update_quality(self):
         updater = Updater()
 
         for item in self.items:
-            if item.name == 'Aged Brie':
+            if item.name == self.AGED_BRIE:
                 updater.aged_brie(item)
-            elif item.name == 'Backstage passes to a TAFKAL80ETC concert':
+            elif item.name == self.BACKSTAGE_PASSES:
                 updater.backstage_passes(item)
-            elif item.name == 'Sulfuras, Hand of Ragnaros':
+            elif item.name == self.SULFURAS:
                 updater.sulfuras(item)
-            elif item.name == 'Conjured Mana Cake':
+            elif item.name == self.CONJURED:
                 updater.conjured(item)
             else:
                 updater.normal_item(item)
-
-
-class Item:
-    def __init__(self, name, sell_in, quality):
-        self.name = name
-        self.sell_in = sell_in
-        self.quality = quality
-
-    def __repr__(self):
-        return "%s, %s, %s" % (self.name, self.sell_in, self.quality)
-    
\ No newline at end of file