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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def directory_name_with_course(self):
        ''' The assignment name in a format that is suitable for a directory name.  '''
        coursename = self.course.directory_name()
        assignmentname = self.title.replace(" ", "_").replace("\\", "_").replace(",","").lower()
        return coursename + os.sep + assignmentname