def addProperty(classInstance, attrName, fget, fset, fdel=None, \
              fdoc="this is magic"):
    """adds a property to an existing class """
    prop = property(fget, fset, fdel, fdoc)
    setattr(classInstance, attrName, prop)
adds a property to an existing class 
recipes/Python/201294_Dynamic_Classes/recipe-201294.py