Ok, this is a question as much as a comment, as I have seen this in all our methods in api.py.  Why do we not use the utility method (defined in this class) model_query?  So the above 2 lines might end up being something like
```
  return model_query(models.Flavor).all()
```

Not only is this more succinct, but also leverage the utility method to properly check for the db session and returns the query object to operate on.  Am I missing something here?  It appears that ironic uses the method as I describe above, except in special cases (and I suspect even those could be refactored a bit)