Pushup to Money class
Inline factory method. Go backward to go forward
Inline factory method in Dollar class
Use instance variable
Test different class equality
Equals compares currencies
Return Money from Times & push it to Money
Replace reference to the subclasses
Delete Dollar class
Removed duplicated assertions
Deleted TestFrancMultiplication test
Deleted Franc class
Simpler addition
Added Expression & Bank
Fake implementation
Added Sum class
Reduce should return a Money whose amount is the sum of the amounts
Reduce
Ugly, ugly, ugly
Add reduce to IExpression interface