I really wanted to make the attribute ip_policy, instead of ippolicy, but whenever I do that and try to pass that in as an argument to subnet, I get

```python
AttributeError: 'dict' object has no attribute '_sa_instance_state'
```

because of this line in the test setUp

```python
subnet_mod.update(subnet)
```

related to SqlAlchemy not liking the fact that Subnet already has a foreign key relationship to IPPolicy.

Any suggestions on how to fix this are welcome.