cattr.py

>>> class C(object):
...    cattr = "hej"
...    def __init__(self, name):
...       self.cattr = name
... 
>>> c = C("hi")
>>> d = C("hej")
>>> d.cattr
'hej'
>>> c.cattr
'hi'
>>> c.__dict__
{'cattr': 'hi'}
>>> C.cattr
'hej'
>>> class C(object):
...    cattr = "Hej"
...    def __init__(self, name):
...       C.cattr = name
... 
>>> c = C("hi")
>>> c.cattr
'hi'
>>> C.cattr
'hi'
>>> d = C("sap")
>>> c.cattr
'sap'
>>> d.cattr
'sap'
>>> c.__dict__
{}

properties.py

>>> class C(object):
...   def __init__(self):
...     self._x = 1
...   @property
...   def x(self): return self._x
...   @x.setter
...   def x(self, val): self._x = val
... 
>>> c = C()
>>> c.x
1
>>> c.x = 2
>>> c.x
2