code: def open_file(self, name, *args, **kwargs):
      if self.is_closed:
          raise StorageError("Storage was closed")
  
      offset, length = self.range(name)
      if self._source:
          # Create a memoryview/buffer from the mmap
          buf = memoryview_(self._source, offset, length)
          f = BufferFile(buf, name=name)
      elif hasattr(self._file, "subset"):
          f = self._file.subset(offset, length, name=name)
      else:
          f = StructFile(SubFile(self._file, offset, length), name=name)
      return f
  
imports: import errno
  import os
  import sys
  from threading import Lock
  from shutil import copyfileobj
  from whoosh.compat import BytesIO, memoryview_
  from whoosh.filedb.structfile import BufferFile, StructFile
  from whoosh.filedb.filestore import FileStorage, StorageError
  from whoosh.system import emptybytes
  from whoosh.util import random_name
label_desc: Use image node_id 5 for calling the CompoundStorage obj's underlying member method code with example usage: obj.open_file(name) and returns: f