code: def _setup_command_prefix():
      prefix = ""
      if sys.platform == "darwin":
          # http://forums.macosxhints.com/archive/index.php/t-43243.html
          # This is an Apple customization to `tar` to avoid creating
          # '._foo' files for extended-attributes for archived files.
          prefix = "COPY_EXTENDED_ATTRIBUTES_DISABLE=1 "
      return prefix
  
imports: import sys
  import os
  from os.path import exists, basename, splitext
  import re
  import codecs
  import logging
  import optparse
  import json
label_desc: Use image node_id 12 for calling a global function with example usage: _setup_command_prefix() and returns: prefix