Minor fixes on listing 4.2
Minor fixes on listing 4.2

RandyAbernethy/ThriftBook,RandyAbernethy/ThriftBook,RandyAbernethy/ThriftBook,RandyAbernethy/ThriftBook,RandyAbernethy/ThriftBook,RandyAbernethy/ThriftBook,RandyAbernethy/ThriftBook,RandyAbernethy/ThriftBook,RandyAbernethy/ThriftBook,RandyAbernethy/ThriftBook,RandyAbernethy/ThriftBook