def __init__(self, unique_id, children, size, params, dyn_params, *args):
    if children:
      raise errors.BlockDeviceError("Invalid setup for file device")
    super(FileStorage, self).__init__(unique_id, children, size, params,
                                      dyn_params, *args)
    if not isinstance(unique_id, (tuple, list)) or len(unique_id) != 2:
      raise ValueError("Invalid configuration data %s" % str(unique_id))
    self.driver = unique_id[0]
    self.dev_path = unique_id[1]
    self.file = FileDeviceHelper(self.dev_path)
    self.Attach()
Initalizes a file device backend.
dataset/ETHPy150Open ganeti/ganeti/lib/storage/filestorage.py/FileStorage.__init__