code: def createNew(cls, store, pathSegments):
          
          if isinstance(pathSegments, basestring):
              raise ValueError(
                  'Received %r instead of a sequence' % (pathSegments,))
          if store.dbdir is None:
              self = cls(store=store, storepath=None)
          else:
              storepath = store.newDirectory(*pathSegments)
              self = cls(store=store, storepath=storepath)
          self.open()
          self.close()
          return self
docs: Create a new SubStore, allocating a new file space for it.