toggler.py

class toggler(object):
    def __init__(self, getter, setter):
        self.getter = getter
        self.setter = setter

    def __enter__(self, *args, **kwargs):
        self.setter(not self.getter())

    __exit__ = __enter__

#use like:

class MyClass(object):
    x = True

    def getx(self):
        return self.x
    def setx(self, x):
        self.x = x

    def some_awesome_fn(self):
        with toggler(self.getx, self.setx):
            print self.x # -> False
        print self.x # -> True

#Or even better

class WebClient(object):
    def javascriptToggled(self):
        return toggler(self.client.isJavascriptEnabled, self.client.setJavascriptEnabled)
    
    def really_awesome_fn(self):
        with self.javascritToggled():
            #Do some stuff