How to set attributes using property decorators?

Is this what you want?

class C(object):
    def __init__(self):
        self._x = None

    @property
    def x(self):
        """I'm the 'x' property."""
        return self._x

    @x.setter
    def x(self, value):
        self._x = value

Taken from http://docs.python.org/library/functions.html#property.