code: def _dev_stat_key(dev_name, stat_name):
      return f"sys/dev{dev_name}/{stat_name}"
  
file_path: guildai/guild/plugins/disk.py
imports: import os
  import platform
  import re
  import sys
  import time
  from guild.plugins.summary_util import SummaryPlugin
label_desc: Use image node_id 4 for calling a global function with example usage: _dev_stat_key(dev_name, stat_name) and returns: str, dev_name, str, stat_name