Update page 'Day 5 and 6 homework - Sloetjes'

Day 5 and 6 homework - Sloetjes.md

@@ -33,7 +33,7 @@ print(vault.treasure)
 attribute deleted!
 gold
 ```
-##### change an attribute of the vault instance
+##### Change an attribute of the vault instance
 ```
 vault.key = 'silver'
 ```
@@ -50,7 +50,46 @@ print(vault.treasure)
 attribute deleted!
 gold
 ```
+##### Another way to implement Vault:
+```
+class Vault:
+    def __init__(self):
+        self._known_attrs = {'treasure': 'gold'}
+        self._attrs = self._known_attrs.copy()
 
+    def __getattribute__(self, name):
+        if name == 'treasure':
+            attrs = object.__getattribute__(self, '_attrs')
+            known_attrs = object.__getattribute__(self, '_known_attrs')
+            if attrs != known_attrs:
+                print('attribute deleted!')
+            return attrs[name]
+        return object.__getattribute__(self, name)
+
+    def __setattr__(self, name, value):
+        if name == 'treasure':
+            attrs = object.__getattribute__(self, '_attrs')
+            attrs[name] = value
+            known_attrs = object.__getattribute__(self, '_known_attrs')
+            if attrs != known_attrs:
+                print('attribute deleted!')
+        else:
+            object.__setattr__(self, name, value)
+vault = Vault()
+print(vault.treasure)
+```
+###### Output:
+```
+gold
+```
+##### Change an attribute of the vault instance
+```
+vault.treasure = 'silver'
+```
+###### Output:
+```
+attribute deleted!
+```
 **To get the other person's class to return "gold", despite any countermeasures they've implemented:**
 ###### It can be achieved by creating a new class that inherits from the `Vault` class and overrides its `_treasure` attribute.
 ```