def __iter__(self):
            root = self.__root
            curr = root[1]
            while curr is not root:
                yield curr[2]
                curr = curr[1]
flatten a nested list.
dataset/ETHPy150Open xraypy/xraylarch/doc/sphinx/ext/backports.py/OrderedDict.__iter__--crossover with--dataset/ETHPy150Open CGATOxford/cgat/CGAT/IOTools.py/flatten