Clean way to disable `__setattr__` until after initialization

A way to disable the __setattr__ until after initialization without changing the self.value = value syntax in the __init__ method is covered here. In short, embed knowledge of initialization in the object and use it in the __setattr__ method. For your Wrapper:

class Wrapper:
    __initialized = False
    def __init__(self, value):
        self.value = value
        self.__initialized = True

    def __setattr__(self, name, value):
        if self.__initialized:
            # your __setattr__ implementation here
        else:
            object.__setattr__(self, name, value)

You are catching all assignments, which prevents the constructor from assigning self.value. You can use self.__dict__ to access the instance dictionary. Try:

class Wrapper:
    def __init__(self, value):
        self.__dict__['value'] = value

    def __setattr__(self, name, value):
        setattr(self.value, name, value)

Another way using object.__setattr__:

class Wrapper(object):
    def __init__(self, value):
        object.__setattr__(self, 'value', value)

    def __setattr__(self, name, value):
        setattr(self.value, name, value)