def _cache_dirs(self):
        for item1 in os.listdir(self.cache_root_dir):
            path1 = os.path.join(self.cache_root_dir, item1)
            if os.path.isdir(path1) and re.match('\d+', item1):
                for item2 in os.listdir(path1):
                    path2 = os.path.join(path1, item2)
                    if os.path.isdir(path2) and re.match('\d+', item2):
                        yield path2
>>> Path('/home/a') + 'bc.d'
dataset/ETHPy150Open Sage-Bionetworks/synapsePythonClient/synapseclient/cache.py/Cache._cache_dirs--crossover with--dataset/ETHPy150Open pypa/pip/tests/lib/path.py/Path.__add__