code: def open_for_scan(self, fname):
      self._fname = fname
      logger.info("open for scan: %s", fname)
      self._fp = open(fname, "r+b")
      self._index = 0
      self._size_bytes = os.stat(fname).st_size
      self._opened_for_scan = True
      self._read_header()
  
imports: import logging
  import os
  import struct
  import zlib
  from typing import TYPE_CHECKING, Optional, Tuple
  import wandb
label_desc: Use image node_id 4 for calling the DataStore obj's underlying member method code with example usage: obj.open_for_scan(fname) without return types