Handle updates of an item.

        :param args:
        :param kwargs:

def put(self, *args, **kwargs):
        """Handle updates of an item.

        :param args:
        :param kwargs:

        """
        self.initialize_put(kwargs.get('id'))

        if not self.has_update_permission():
            self.set_status(403, self.status_message('Creation Forbidden'))
            self.finish()
            return

        for key, value in self.model.items():
            if self.json_arguments.get(key) != value:
                self.model.set(key, self.json_arguments.get(key))

        if not self.model.dirty:
            self.set_status(431, self.status_message('No changes made'))
            self.finish(self.model.as_dict())
            return

        result = yield self.model.save()
        if result:
            self.set_status(200, self.status_message('Updated'))
        else:
            self.set_status(507, self.status_message('Update Failed'))
        self.add_headers()
        self.finish(self.model.as_dict())