[chapter 06 #104] Extract Method: add test before refactoring
[chapter 06 #104] Extract Method: no local variables
[chapter 06 #105] Extract Method: using local variables
[chapter 06 #107] Extract Method: reassigning a local variable
[chapter 06 #108] Inline Method: add ReadMe
[chapter 06 #109] Inline Method: add example before refactor
[chapter 06 #109] Inline Method: refactored example