Added more test files from lectures.

test23.py

@@ -0,0 +1,23 @@
+class Vault:
+    def __init__(self):
+        self._treasure = 'gold'
+        self._original_attrs = self.__dict__.copy()
+
+    @property
+    def treasure(self):
+        if self.__dict__ != self._original_attrs:
+            print('Attribute deleted!')
+        return self._treasure
+    def stuff(self):
+        ...
+
+    def __setattr__(self, key, value):
+        self.__dict__[key] = value
+        if key != '_original_attrs' and hasattr(self, '_original_attrs') and self.__dict__ != self._original_attrs:
+            print('Attribute deleted!')
+
+    def __call__(self, *args):
+        print(f"attempt to call {args}")
+
+v = Vault()
+v(1,2,3)