[Replace type code with state/strategy] initial codes
[Replace type code with state/strategy] create person and set emploee to person
[Replace type code with state/strategy] delete person and use employee directly
[Move Field] initial codes
[Move Field] add interest in the AccountType class and use getter in Account class
[Move Field] delete interest in Account class
[Move Field] self encapsulation when many methods use the interest attribute
[Move Field] modify the getter method in Account method
[Move Field] delete and inline the getter and setter
[Remove Assignments to Parameters] initial codes
[Remove Assignments to Parameters] use temporary variable to substitute assignment
[Remove Assignments to Parameters] add final to the parameters
[Remove Assignments to Parameters] add explanation
[Separate Query from Modifier] initial codes
[Separate Query from Modifier] add bad smell explanation
[Separate Query from Modifier] create a pure Query method
[Separate Query from Modifier] use new Query method to substitute the returing value
[Separate Query from Modifier] modify caller to use two separated methods
modify the return value of the modifier method to void
rename