code: def open_for_append(self, fname):
      # TODO: implement
      self._fname = fname
      logger.info("open: %s", fname)
      self._fp = open(fname, "wb")
  
imports: import logging
  import os
  import struct
  import zlib
  from typing import TYPE_CHECKING, Optional, Tuple
  import wandb
label_desc: Use image node_id 3 for calling the DataStore obj's underlying member method code with example usage: obj.open_for_append(fname) without return types