def __enter__(self):
        ctx = self.ctx
        self.stack.append(self.ctx)
        for var, role in self.bindings.iteritems():
            role.assign(getattr(ctx, var))
        return ctx
take an existing entity and a modified entity and check for changes.
dataset/ETHPy150Open amolenaar/roles/roles/context.py/ManagedContext.__enter__--crossover with--dataset/ETHPy150Open saltstack/salt/salt/states/bigip.py/_check_for_changes