I don't get it, because, for 0.9, we import FunctionElement from sqlalchemy.sql.functions, not from sqlalchemy.sql.expression. This is what I'm suggested:

```
try:
    from sqlalchemy.sql import functions
except ImportError:  # SQLA < 0.9
    from sqlalchemy.sql import expression as functions
```

and then use functions.FunctionElement, functions._FunctionGenerator, and functions.Function in the code. Anything wrong with that. My apologies if I'm missing your point here.