def mkdir(self, parent, name):
        pid = None
        cid = None
        if isinstance(parent, Directory):
            pid = parent.cid
        else:
            raise('Invalid Directory instance.')
        cid = self._req_files_add(pid, name)['cid']
        return self._load_directory(cid)
Adds the given statistics/logging string to the store of statistics info.
dataset/ETHPy150Open shichao-an/115wangpan/u115/api.py/API.mkdir--crossover with--dataset/ETHPy150Open BD2KGenomics/toil/src/toil/jobStores/abstractJobStore.py/AbstractJobStore.writeStatsAndLogging