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Chapter2: Fix type mismatch errors by passing Strings instead of Ints to Kitten constructor
Chapter2: Fix type mismatch errors by passing Lists instead of Sets to Kitten and BuyerPreferences constructors
Chapter3: Rename UsedKittenMain to PreownedKittenMain
Chapter5: Remove unused import statement
Chapter5: Remove unused import statements
Chapter5: Remove unused import statements
Chapter5: Replace junit-interface-0.10-M3 dependency with stable version 0.10 to make it consistent with the book
Chapter6: Remove unused import statement
Chapter6: Remove unused import statements
Chapter6: Remove unused import statement
Chapter6: Remove unused import statements
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Chapter7: Remove unused import statements
Chapter7: Remove unused import statement
Chapter7: Remove unused import statement
Chapter7, Chapter6: Replace junit-interface-0.10-M3 dependency with stable version 0.10 to make it consistent with the book
Chapter7: Remove unused import statements
Chapter8: Remove unused import statement
Chapter8: Remove unused import statements