diff --git a/python/formation/classes.txt b/python/formation/classes.txt
index 5f4b5bc..085c9d6 100644
--- a/python/formation/classes.txt
+++ b/python/formation/classes.txt
@@ -72,6 +72,124 @@ possibilité en python d'héritage multiple::
     class A(B, C): pass
 
 
+attribut d'objets et de classes
+----------------------------------
+
+>>> o = object()
+>>> o
+<object object at 0x7f77c9cda0d0>
+>>> class C(object): pass
+... 
+>>> class C: pass
+... 
+>>> c = C()
+>>> c.a = 3
+>>> c.a
+3
+>>> vars(c)
+{'a': 3}
+>>> c.__dict__
+{'a': 3}
+>>> C.__dict__
+{'__module__': '__main__', '__doc__': None}
+>>> C.c = 5
+>>> C.__dict__
+{'c': 5, '__module__': '__main__', '__doc__': None}
+>>> c.c
+5
+>>> c.z = 3
+>>> c.z
+3
+>>> c.__dict__
+{'a': 3, 'z': 3}
+>>> C.__dict__
+{'c': 5, '__module__': '__main__', '__doc__': None}
+>>> class MaKlass:
+...   def unefonction(self, x):
+...     print x 
+... 
+>>> MaKlass.__dict__
+{'__module__': '__main__', '__doc__': None, 'unefonction': <function unefonction at 0x7f77c5b0c488>}
+>>> k = MaKlass()
+>>> k.__dict__
+{}
+>>> def autrefonc(self, x)
+  File "<stdin>", line 1
+    def autrefonc(self, x)
+                         ^
+SyntaxError: invalid syntax
+>>> def autrefonc(self, x):
+...   print x
+... 
+>>> k.autrefonc = autrefonc
+>>> k.__dict__
+{'autrefonc': <function autrefonc at 0x7f77c5b0c500>}
+>>> MaKlass.__dict__
+{'__module__': '__main__', '__doc__': None, 'unefonction': <function unefonction at 0x7f77c5b0c488>}
+>>> MaKlass.unefonction(k, "toto")
+toto
+>>> k.unefonction("toto")
+toto
+>>> k.__dict__
+{'autrefonc': <function autrefonc at 0x7f77c5b0c500>}
+>>> MaKlass.toto = "test"
+>>> k.__dict__
+{'autrefonc': <function autrefonc at 0x7f77c5b0c500>}
+>>> k.toto
+'test'
+>>> 
+
+
+le __dict__ avec l'héritage de classe 
+-------------------------------------------
+
+
+>>> class A(object): pass
+... 
+>>> A.__dict__
+dict_proxy({'__dict__': <attribute '__dict__' of 'A' objects>, '__module__': '__main__', '__weakref__': <attribute '__weakref__' of 'A' objects>, '__doc__': None})
+>>> class B(A): 
+...   b = 3
+... 
+>>> class C(B):
+...   c = 2
+... 
+>>> c = C()
+>>> o = C()
+>>> o.__dict__
+{}
+>>> o.c
+2
+>>> o.b
+3
+>>> o.__class__
+<class '__main__.C'>
+>>> o.__class__.__dict__
+dict_proxy({'__module__': '__main__', 'c': 2, '__doc__': None})
+>>> 
+
+
+method resolution object 
+-----------------------------
+
+>>> class A(object): pass
+... 
+>>> A.__mro__
+(<class '__main__.A'>, <type 'object'>)
+>>> class B(A): pass
+... 
+>>> B.__mro__
+(<class '__main__.B'>, <class '__main__.A'>, <type 'object'>)
+>>> class C(A, B): pass
+... 
+Traceback (most recent call last):
+  File "<stdin>", line 1, in <module>
+TypeError: Error when calling the metaclass bases
+    Cannot create a consistent method resolution
+order (MRO) for bases A, B
+>>> 
+
+
 introspection contre encapsulation
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~