code: def freeze():
      cmd = [sys.executable, "-m", "pip", "freeze"]
      log.debug("running pip freeze: %s", cmd)
      try:
          out = subprocess.check_output(cmd, stdin=subprocess.DEVNULL)
      except Exception as e:
          if log.getEffectiveLevel() <= logging.DEBUG:
              log.exception("reading pip freeze")
          else:
              log.warning("error reading pip freeze: %s", e)
          return None
      else:
          return out.decode().splitlines()
  
imports: import logging
  import os
  import re
  import subprocess
  import sys
  from guild import util
label_desc: Use image node_id 18 for calling a global function with example usage: freeze() and returns: out, None