OOP finished

OOP/wiki.txt

@@ -109,4 +109,49 @@
     It specify what are the functions and variable the instance of
     a class(object) has access to.
 
--> Dunder methods:
+-> Dunder methods:
+
+    Dunder methods allow us to modify and implement built-in function
+    of objects. This allow us to implement our own custom logic for
+    built-in function which work for objects. The modification only
+    works for that same object only and if we apply it on different
+    object then it would behave as usual(or as implemented for other
+    object)
+
+
+    for ex:
+
+        class Toy():
+            def __init__(self, color, age):
+                self.color = color
+                self.age = age
+                self.my_dict = {
+                    'name' : 'Yoyo',
+                    'has_pets' : False
+                }
+
+            def __str__(self):
+                return f'{self.color}'
+
+            def __len__(self):
+                return 5
+
+            def __call__(self):
+                return ('yes??')
+
+            def __getitem__(self, i):
+                return self.my_dict[i]
+
+
+        action_figure = Toy('red',0)
+        print(action_figure.__str__())
+        print(str(action_figure))
+        print(len(action_figure))
+        print(action_figure())
+        print(action_figure['name'])
+
+-> MRO (Method Resolution order):
+
+    MRO allow us to determine the order in which 
+    the Inheritance need to be processed. This 
+    order is determined using Depth first search.