code: def get_all_courses(self):
          
          course_ids = [f[0:len(f)-1] for f in self._filesystem.list(folders=True, files=False, recursive=False)]  # remove trailing "/"
          output = {}
          for courseid in course_ids:
              try:
                  output[courseid] = self.get_course(courseid)
              except Exception:
                  get_course_logger(courseid).warning("Cannot open course", exc_info=True)
          return output
docs: :return: a table containing courseid=>Course pairs