code: def _safe_filename(s):
      if not s:
          return s
      return re.sub(r"\W+", "-", s).strip("-") or "-"
  
imports: import hashlib
  import logging
  import os
  import re
  from guild import click_util
  from guild import cmd_impl_support
  from guild import remote
  from guild import util
  from guild import var
  from guild.commands import runs_impl
label_desc: Use image node_id 2 for calling a global function with example usage: _safe_filename(s) and returns: unknown, s