Having the symbol at the context root and the value under ``benifit`` looks a little odd. Is there a design consideration that prevents us from creating a Currency class that can hold both properties? Much like measurements,  an amount of money is meaningless without a symbol.

We should also consider using [ISO currency codes](http://www.xe.com/iso4217.php) to prevent ambiguity

```python
amount = Currency('USD', 19.95)
str(amount.convert_to('GBP'))