code: def _zeo_key(self, key, new_type=OOBTree):
          
          zeo_key = self.zeo.get(key, None)
  
          if zeo_key is None:
              zeo_key = new_type()
              self.zeo[key] = zeo_key
  
          return zeo_key
docs: Get key from the :attr:`zeo` database root. If the key doesn't exist,
          create it by calling `new_type` argument.
  
          Args:
              key (str): Key in the root dict.
              new_type (func/obj): Object/function returning the new instance.
  
          Returns:
              obj: Stored object, or `new_type`.