code: def file_length(self, name):
      info = self._dir[name]
      return info["length"]
  
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 8 for calling the CompoundStorage obj's underlying member method code with example usage: obj.file_length(name) and returns: info