whitespaces for ch9, forgotten one
whitespaces for ch9, forgotten one

raventid/coursera_learning,raventid/coursera_learning,raventid/coursera_learning,raventid/coursera_learning,raventid/coursera_learning,raventid/coursera_learning,raventid/coursera_learning,raventid/coursera_learning,raventid/coursera_learning,raventid/coursera_learning